EIBOS Cyclopes vs SUNLU FilaDryer S4

Who this comparison is for

This page is for anyone choosing between these two specific dryers: the EIBOS Cyclopes in its US 110 V version, and the SUNLU FilaDryer S4 in Black. They're different sizes. The Cyclopes is a two-spool box, and the S4 is a four-spool box with a 458 mm long body, so the first question is how many spools you need dry at the same time. If you're still deciding whether you need a heated dryer at all, start with our filament dryer vs dry box guide, and for what to check in any dryer, see how to choose a filament dryer. We've also compared each of these with another dryer: the EIBOS Cyclopes vs Sovol SH02 and the SUNLU FilaDryer S4 vs Creality SpacePi X4. For more dryers, see the filament dryer shortlist.

How we compared them

This is a research-based comparison. Every figure below comes from each maker's own product pages, user manuals, wiki, and blog, listed in the sources. We haven't tested either dryer, so nothing here is a measured result of ours. Where a maker describes its own product, such as SUNLU's "world's first large-capacity filament dryer," we label it as the maker's claim.

Both manuals are image-based PDFs with no text layer, so we read them from the rendered pages. We used only the words printed in them, not anything shown in their photos or drawings. Each maker's documents disagree with each other in places, which we point out as we go and sum up at the end.

Side-by-side specs

Spool count and fit

This is the biggest difference.

• EIBOS Cyclopes. EIBOS's manual gives a "Maximum Capacity" of "Double Reels ф217x80mm" or "Single Reel ф217x174mm." The product page tech specs repeat that and add a "Max Spool Size" row giving ф217 × 170 mm for one spool. They also say "By utilizing expansion parts, the capacity can be increased up to ф250x170mm," without saying what those parts are or whether they come in the box. The manual's package list is the manual, one Teflon tube, and four bearing units, so plan around ф217 mm. EIBOS's description says the box holds "four rolls of 0.5kg or two rolls of 1kg filament." The manual says to "leave the gap between the spools for better heating."
• SUNLU FilaDryer S4. SUNLU says the S4 dries "up to 4 rolls of 1kg filament simultaneously" in an internal space of 450 × 210 × 211 mm. None of SUNLU's pages, wiki, or manual gives a maximum spool diameter or width. The manual's packing list includes eight rollers.

So the S4 holds twice as many 1 kg spools. The Cyclopes gives you published limits to check against, including room for one spool up to 174 mm wide. With the S4, all you can check is the 211 mm and 210 mm inside dimensions, and "holds four 1 kg spools" doesn't mean it holds every brand's 1 kg spool. Measure your spools' outer diameter and width before buying either.

Temperature: 70 °C on both, with an EIBOS caveat

SUNLU is consistent. Its product page, wiki, store page, and blog all give 70 °C as the top. Its product page and wiki say that's enough "for fast drying of specialty filaments such as PA and PC." Its own comparison blog is more cautious. It lists "Max temp still limited to 70°C" as a con and says to choose the S4 if "You don't need temperatures above 70°C." SUNLU doesn't publish the S4's lowest setting.

EIBOS's documents mostly say 70 °C. Its manual lists a "Temperature Control Range: ≤70℃" and says you can set the target temperature from "0℃ to 70℃." Its product page data sheet says "≤ 70℃," and its description says "up to 70 degrees." The tech specs table on the same page says "≤80°C." EIBOS doesn't explain the difference, so we've gone with the 70 °C its manual gives. The manual also notes: "The measured temperature is the temperature of the area where the sensor is located, not the temperature of anywhere in the machine."

So plan as if both stop at 70 °C. If your filament maker's drying temperature is higher than that, neither dryer reaches it.

Airflow and heating design

• EIBOS Cyclopes. EIBOS pairs a 100 W PTC heater with a built-in fan "designed to circulate the hot air inside the filament dryer box." It says this is "different from applying normal heater 48W PI heating pad," and calls its heater "more durable, energy-saver, and environmentally friendly." Those are EIBOS's claims. It gives a temperature control precision of ±2 °C.
• SUNLU FilaDryer S4. SUNLU uses a PTC heater with "Dual side circulation fans combined with a bottom heating fan," which it says "maintain chamber temperature within ±3°C." Its store page says the eight filament holes help the design expel "interior humidity, preventing moisture accumulation." That's SUNLU's claim.

SUNLU's pages disagree on the S4's heater size:

Whichever figure is right, it's several times the Cyclopes's 100 W, in a box built for twice as many spools.

The two precision figures aren't a like-for-like test. EIBOS describes how closely it controls temperature, and SUNLU describes how even the chamber is. Neither maker says how it measured its figure.

Humidity readout and control

The Cyclopes has a separate digital hygrometer, which EIBOS says shows "A dramatic drop in the humidity level" with a "measurement range from 10%-99%." It reads the humidity, but nothing on EIBOS's page or manual says the dryer acts on it.

The S4 shows relative humidity on its touch screen and has two modes, according to its manual. "MO 1" is a time mode that shuts down after the countdown. In "MO 2," the humidity mode, after the countdown ends, "when the humidity slowly rises to 50% or the User-set humidity value, it will automatically start heating until the humidity drops to 25%." You can set the starting value from 30% to 50%. The manual adds: "If the humidity does not decrease to the target value, please check whether the top cover is properly closed, or appropriately increase the set heating temperature by 5°C."

If you want spools kept dry between prints without restarting the dryer yourself, the S4 documents a way to do it, and the Cyclopes doesn't.

Controls, timer, and settings

The Cyclopes has an LCD panel with buttons. Its manual has you set the target temperature, then the hours and minutes. Hours run "from 0 to 24," and going above 24 switches to "the unlimited timing status." The product page gives the default as 6 hours. EIBOS has no presets, but its manual includes a recommended settings table.

The S4 has a touch screen. Its manual lists a filament type setting that uses "the recommended temperature parameters," a drying time of up to 99 hours, a °C/°F switch, and an LED light setting. SUNLU's store page says the presets cover PLA, ABS, PETG, TPU, PA, and PC and are "based on testing data," which is SUNLU's claim.

Here are the settings each maker prints in its manual. Neither says how wet the filament was or how the times were chosen, so read them as each maker's guidance rather than drying results.

The two makers don't agree. EIBOS suggests a hotter setting for PETG and a cooler one for ABS, ASA, and PVA than SUNLU does, and a longer minimum time for nylon. EIBOS says its table "is for reference only." Both makers cap PC and nylon at about 70 °C, which is their dryer's limit rather than proof those materials dry fully at that heat. Check your filament maker's drying guidance first.

EIBOS's manual also includes a moisture chart from what it calls "EIBOS laboratory testing (PA-CF, 70℃)." It shows moisture content falling from 3.25% to 1.84% over 8 hours. EIBOS says the data "is for reference only," and it doesn't say how wet the PA-CF was to start or how it was measured, so we can't compare it with anything. SUNLU publishes no drying curve for the S4.

Printing while drying

Both makers say you can print from the dryer. Neither names a printer or multi-material feeder it has tested with on the pages and manuals we checked.

• EIBOS Cyclopes. EIBOS says "Drying while printing, the dryer function as both storage box and filament holder." It lists ten filament holes, "six on the top, two on the front, and two on the back," and the manual's package list has one Teflon tube. The data sheet lists 1.75 mm filament and says you "need to switch the Teflon for 2.85mm filament," while the description lists 1.75, 2.85, and 3.00 mm.
• SUNLU FilaDryer S4. SUNLU says the S4 "supports simultaneous filament feeding for up to 4 printers" through eight filament holes, and lists 1.75, 2.85, and 3.0 mm filament. Its manual says to cut the Teflon tube to 8 cm and thread the filament through "the filament output of the filament dryer and the Teflon tube." SUNLU also says the S4 is "Compatible with all printer models." That's a general claim with no tested printer named, so we don't treat it as a confirmed fit for any particular machine. SUNLU's blog lists "Supports multi-color AMS-style setups" as a pro and answers "Do they work with Bambu Lab AMS?" with "Absolutely. Many users pair the S4 or E2 with AMS/AMS HT systems." That points to user setups and names no tested AMS model or setup steps, so we don't treat it as a documented fit.

Power, noise, and footprint

EIBOS rates the Cyclopes at 100 W. SUNLU rates the S4 at 300 W on its product page and wiki and 320 W on its store page, and its blog's comparison table gives 320–350 W. Neither maker publishes energy use per drying run.

Neither maker gives a noise figure for these dryers. SUNLU's blog says the S4 has fans "but remain[s] quiet enough for desktop use," which isn't a measurement. EIBOS says nothing about noise on the pages and manual we checked.

The S4 is much bigger and heavier. SUNLU lists it at 458 × 218 × 312 mm and 4.8 kg. EIBOS lists the Cyclopes at 213 × 280 × 305 mm without labelling the axes, and at 1.5 kg in its manual and tech specs, or 1.6 kg in its data sheet.

Safety features each maker lists

SUNLU lists "PTC thermistor, mechanical temperature switch, and software monitoring" as three levels of protection, and says "Real-time temperature monitoring triggers alerts in case of anomalies."

EIBOS's product page lists no overheat protection, fan monitoring, or alarm for the Cyclopes. Its manual's "Before Using" section gives warnings instead. It says not to leave the power cord plugged in when the dryer isn't in use, not to touch the heating hole "in order to avoid scald," to cut off power when it's unattended "to prevent accidental fire," and to stop and contact EIBOS if it malfunctions rather than fix it yourself. That doesn't mean the Cyclopes has no protection, only that EIBOS doesn't document any on the page and manual we checked.

What each maker says it's for

• EIBOS Cyclopes. EIBOS says it is "specifically made for the purpose of drying 3D printer filament," and that its space is "suitable for parallel use of multiple 3D printers." It lists nylon, PLA, PETG, TPU, ABS, silk, carbon fiber, and wood filaments.
• SUNLU FilaDryer S4. SUNLU calls it "the world's first large-capacity filament dryer," built "for makers who need a serious filament dryer for 3D printing across multiple colors, materials, or machines." Its blog aims it at "Makers running multiple printers, multi-color projects, or workshops."

EIBOS

EIBOS Cyclopes Filament Dryer (US 110 V, 2-spool)

Best for

Drying two narrow 1 kg spools at once, or one wide spool.

Skip this if

You need to dry above 70 °C.

Specs, strengths, and limitations

Capacity

Two reels up to ф217 × 80 mm, or one reel up to ф217 × 174 mm (EIBOS Maximum Capacity; its Max Spool Size row says ф217 × 170 mm); up to ф250 × 170 mm with expansion parts (EIBOS)

Part rated to

70 °C (your printer's own hotend limit may be lower)

Maker notes

EIBOS manual and tech specs: rated power 100 W (PTC heater), timer 1 min–24 h or unlimited, temperature precision ±2 °C; the manual sets hours 0–24 (past 24 = unlimited) and minutes 0–59. Its description gives a 10–99% humidity range, '0-24hrs' and a 6 h default; a product image says 1 h–24 h. EIBOS lists product size 213 × 280 × 305 mm (axes not labelled); net weight 1.6 kg in its data sheet and 1.5 kg in its manual and tech specs. Package contents (manual): user manual ×1, Teflon tube ×1, bearing unit ×4; EIBOS's product image also shows an A76/LR44 button battery for the hygrometer. Temperature: EIBOS's user manual gives 'Temperature Control Range: ≤70℃' and a 0–70 ℃ setting range, matching its data sheet ('≤ 70℃') and description; only the product page tech specs say '≤80°C'. 70 °C is recorded per the manual. 10 outlet holes and a built-in fan (EIBOS). The spec table lists ф1.75 mm filament; EIBOS copy also lists 2.85 / 3.00 mm.

Strengths

• Manufacturer states it holds two spools up to ф217 × 80 mm, or one wide spool up to ф217 × 174 mm.
• Manufacturer lists a timer from 1 minute to 24 hours, or unlimited.
• Manufacturer states ±2 °C temperature precision with a 100 W PTC heater and fan.

Limitations

• EIBOS's manual gives 70 °C, but its product page tech specs say ≤80 °C.
• Two-spool drying is limited to spools up to 80 mm wide (EIBOS).

View on Amazon ↗ (opens Amazon in a new tab)Details checked 2026-10-06 against the manufacturer. Price and availability are on Amazon.

SUNLU

SUNLU FilaDryer S4 (Black, 4-spool dryer)

Best for

Multi-printer or multi-material setups that need four 1 kg spools dried and fed at once.

Skip this if

You only dry one spool at a time or have limited bench space.

Specs, strengths, and limitations

Capacity

Four 1 kg spools; internal size 450 × 210 × 211 mm (SUNLU). Maximum spool diameter and width are not stated.

Outer size

458 × 218 × 312 mm

Part rated to

70 °C (your printer's own hotend limit may be lower)

Maker notes

SUNLU lists product size 458 × 218 × 312 mm (L×W×H); the store page says this includes the height of the tripod. SUNLU states heater power inconsistently: '350W PTC heater' with rated power 300 W (sunlu.com product page and wiki); 'Built-in 300W PTC heater' in the store bullets but 'a heating power of 330W' in the store description, with rated power 320 W (store page); its blog gives '320–350 W'. Dual side circulation fans plus a bottom heating fan; SUNLU states chamber temperature is balanced within ±3 °C. Humidity mode: drying starts when humidity reaches the set value (30–50%) and stops at 25% (SUNLU). Triple protection: PTC thermistor, temperature switch and software monitoring (SUNLU). Filament diameters 1.75 / 2.85 / 3.0 mm; SUNLU states it can feed up to 4 printers; the store page lists 2 × 100 cm and 4 × 8 cm PTFE tubes; the user guide packing list shows 2 × 100 cm Teflon tubes, a power cord and 8 rollers. The Amazon listing gives 460 × 220 × 310 mm, a 350 W heater and a 35–70 °C range; SUNLU's own figures are used here. SUNLU's user guide gives a drying timer of up to 99 h, a touch screen with filament-type presets, and two modes: MO1 time control (shuts down after countdown) and MO2 humidity control (after the countdown, reheats when humidity rises to 50% or a user-set 30–50% and stops at 25%).

Strengths

• Manufacturer states it can dry four 1 kg spools at once in a 450 × 210 × 211 mm chamber.
• Manufacturer states side and bottom fans keep chamber temperature within ±3 °C.
• Manufacturer lists triple safety protection (PTC thermistor, temperature switch, software monitoring with alerts).

Limitations

• Large footprint: SUNLU lists 458 × 218 × 312 mm.
• 70 °C maximum, and SUNLU does not state a maximum spool diameter or width, so check large spools before buying.
• SUNLU's own pages disagree on heater power (300, 330 or 350 W) and rated power (300 or 320 W).

View on Amazon ↗ (opens Amazon in a new tab)Details checked 2026-10-06 against the manufacturer. Price and availability are on Amazon.

Verdict: which should you buy?

For three or four spools at once, the SUNLU FilaDryer S4 is the one documented for the job. It holds four 1 kg spools and adds presets, a 99-hour timer, a humidity mode that restarts heating when the box gets damp, and three listed levels of safety protection with alerts. It's also 458 mm long, about three times as heavy, and three times the rated power. For one or two spools, the EIBOS Cyclopes covers the same 70 °C in a much smaller box, and it's the only one of the two with published spool-size limits, including one spool up to ф217 × 174 mm. Neither suits filament that needs more than 70 °C.

Choose the EIBOS Cyclopes if…

• You dry one or two spools at a time and want a smaller, lighter box.
• You want published spool limits to check against, including a documented fit for one spool up to ф217 × 174 mm.
• You're happy setting temperature and time yourself and reading humidity from a separate hygrometer.

Choose the SUNLU FilaDryer S4 if…

• You dry three or four 1 kg spools at once, or feed up to four printers.
• You want filament presets, a timer up to 99 hours, and a humidity mode that restarts heating when the box gets damp.
• You want SUNLU's listed three-level safety protection with alerts, and you have the bench space for a 458 mm long box.

Safety and limits

How this page was checked

Every specification, setting, and claim above comes from the maker documents in the sources section, retrieved on 2026-10-14. We haven't tested either dryer for this page, so nothing here is a measured result of ours. Both user manuals are image-based PDFs, so we read them from the rendered pages and used only their printed text. We found the Cyclopes manual on EIBOS's download page and the S4 user guide on SUNLU's product page. EIBOS's documents disagree on maximum temperature (70 °C in the manual, data sheet, and description; ≤80 °C in the tech specs), single-spool width (174 mm and 170 mm), net weight (1.5 kg and 1.6 kg), the timer's lower end (1 minute in the manual and tech specs; 0–24 hours in the description), and filament diameters, so we've used the manual where they differ and reported the rest. EIBOS's description also gives an internal space of 245 × 305 × 355 mm, the same as its listed package size, so we haven't used it. SUNLU's documents disagree on heater power (300, 330, or 350 W, and 320–350 W in its blog), rated power (300 or 320 W, and 320–350 W in its blog table), and the PTFE tubes in the box (two 100 cm and four 8 cm on the store page; two 100 cm in the manual's packing list), so we've reported each with where it appears. SUNLU's blog "Absolutely" on AMS use cites what users do and names no tested setup, so we haven't treated it as a documented fit, and neither maker documents a tested fit with any printer or feeder. Customer reviews and Q&A on both stores weren't used. Read more in our editorial standards and affiliate disclosure.

Dryers & dry boxes: what to check before you buy ↗