SUNLU Filament Dryer S4, four-spool 3D printer dryer

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Product guide

SUNLU Filament Dryer S4, four-spool 3D printer dryer

The SUNLU Filament Dryer S4 is a four-spool dryer and storage box for 3D printer filament. Its listing describes automatic humidity-triggered drying, three internal fans and connections for feeding up to four printers, making it aimed at multi-spool setups rather than users drying one roll at a time.

At a glance

Room for four 1 kg spools is intended for multi-colour or multi-printer workflows.
Automatic drying is described as starting when humidity reaches the chosen range and stopping below 25%.
The listing specifies three fans and claims temperature balance within ±3℃.
Eight feed holes are stated, alongside a claim of connection to four printers at once.

Price

£84.99Save 15%

Reference price: ~~£99.99~~

Price checked: 12 Nov 2026

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Often bought together

Filament Joiner SUNLU Filament Connector with 200PCS PTFE Sleeve for 3D Printer Filament 1.75mm, 240°C Fast Heating Filament

£36.99

ELEGOO PLA+ 3D Printer Filament 1.75mm Black 4KG | PLA Plus Tougher and Stronger, Dimensional Accuracy +/- 0.02mm, 4 Pack 1kg

£43.99

Pros and cons

Pros

Four-spool capacity can reduce the need to rotate rolls through a smaller dryer.
Selectable humidity control and automatic start/stop can reduce manual monitoring.
Three fans are intended to circulate air across the enclosure.

Technical specifications

16 specifications

Identity
Brand	SUNLU
Model	SUNLU Filament Dryer S4

Dimensions and installation
Weight listed	4 Kilograms

Materials and protection
Material listed	S4 Dryer Filament
Colour	black

Capacity and connections
Spool capacity claimed	4 spools 1KG 3D Printer Filament simultaneously
Printer connections claimed	supports connection to 4 printers simultaneously
Feed holes described	8 Feed Holes

Heating and air circulation
Heater	350W PTC heater
Warm-up claim	In just 30 minutes, it heats up from 25℃ to 50℃
Fans	three build-in fans – two circulating fans on the sides and 1 on the bottom
Temperature balance claimed	within ±3℃

Humidity control
Adjustable humidity range	30%~50%
Drying stop threshold	below 25%

Compatibility
Printer type claimed	all FDM 3D printers
Filament compatibility claimed	accommodating 99.99% of filaments in the market

What to know before buying

Listing claims such as four spools, four printer connections, 350W heating and the stated humidity behaviour are manufacturer descriptions, not independently verified performance measurements. The claimed 30-minute warm-up applies to heating from 25℃ to 50℃. The listing says the selected humidity range is 30%~50% and drying stops below 25%, so operation may not match a single fixed humidity target.

Who is it for?

A good fit for

Users drying or storing several filament spools together.
Multi-colour or multi-printer FDM setups that can make use of multiple feed paths.
Buyers who want selectable humidity-triggered drying rather than only manual operation.

Less suited to

Users who only need a compact dryer for one spool.
Buyers needing independently verified heating, humidity-control or compatibility performance.

SUNLU Filament Dryer S4, four-spool 3D printer dryer · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.6 / 5 · 653 ratings

5 stars81%81%
4 stars12%12%
3 stars3%3%
2 stars1%1%
1 star3%3%

Customer feedback describes the dryer as easy to use and reports positive experiences with drying performance, print quality, customisable settings and appearance. Heating feedback is mixed: customers report quick heating but also note that it generates a fair amount of heat. That concern is relevant for a heated enclosure, while the four-spool capacity and humidity features are product claims rather than proof of individual customer outcomes.

Positive themes

Customer feedback describes drying performance and day-to-day operation positively.
Customers mention ease of use, print quality, customisable settings and appearance.

Mixed feedback

Heating feedback is mixed, with reports of quick heating alongside comments that the unit generates a fair amount of heat.

Frequently asked questions

How many spools can the SUNLU S4 hold?

The listing claims it can hold four 1 kg filament spools at once.

Does the S4 adjust drying automatically?

The listing describes adjustable humidity from 30%~50%, with drying starting when humidity reaches the selected range and stopping below 25%.

Can it feed more than one printer?

The listing claims connections for four printers simultaneously and describes eight feed holes. Confirm the selected listing and your printer arrangement if this capacity is essential.

How quickly does it heat up?

The claimed warm-up is 30 minutes from 25℃ to 50℃. This is a listing claim, not an independently verified result.