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Product guide

SUNLU Filament Dryer S4, four-spool

The SUNLU Filament Dryer S4 is a four-spool dry box for 3D printer filament. Its listed automatic humidity control and three-fan circulation are intended for drying several spools together, while the claimed heating figures and listed dimensions are worth checking against your setup before buying.

At a glance

The listing claims capacity for four 1 kg spools at the same time, which may suit multi-spool or multi-printer workflows.
Three built-in fans are described as circulating air around the box, with a claimed internal temperature balance within ±3℃.
Automatic humidity control is described for Mode 2, with drying starting at a selected humidity range and stopping below 25%.
The listing claims a 350W PTC heater and a 30-minute rise from 25℃ to 50℃.

Price

£84.98Save 15%

Reference price: ~~£99.99~~

Price checked: 12 Nov 2026

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Pros and cons

Pros

Four-spool capacity can reduce the need to dry spools one at a time.
The described automatic humidity control and three-fan circulation provide more than basic enclosed storage.
Customer feedback reports positive impressions of drying performance and value.

Technical specifications

12 specifications

Identity
Brand	SUNLU
Model	SUNLU Sécheur à filament S4

Capacity and heating
Spool capacity	4 spools 1KG 3D Printer Filament simultaneously
Heater	350W PTC heater
Heating claim	In just 30 minutes, it heats up from 25℃ to 50℃
Temperature balance claim	within ±3℃

Humidity control
Mode 2 humidity range	30%~50%
Drying stop threshold	below 25%

Dimensions and installation
Dimensions listed	21.1D x 21W x 21.1H centimetres

Materials and protection
Material listed	Plastic Filament
Temperature protection claimed	PTC, temperature switch, and software protection

Air circulation
Fans claimed	three build-in fans – two circulating fans on the sides and 1 on the bottom

What to know before buying

Listing details to confirm

The listing details are inconsistent: the model is given in French as “SUNLU Sécheur à filament S4”, the stated box dimensions are 21.1D x 21W x 21.1H centimetres, and package dimensions are separately listed as 51.5 x 35.5 x 28 cm; 4 kg. Weight appears as both “4 Kilograms” and “4 kg”. The heater, humidity thresholds, capacity and temperature figures are manufacturer claims, not independently verified measurements. Confirm the physical dimensions and the operating details relevant to your filament before purchase.

Who is it for?

A good fit for

3D printer owners who want to dry up to four 1 kg spools together.
Users managing several filament spools who can accommodate the listed product dimensions.
Buyers who want the listed humidity-triggered drying mode rather than storage alone.

Less suited to

Anyone who needs verified performance measurements or independently confirmed humidity and temperature control.
Buyers needing a compact unit if the stated product dimensions do not fit their workspace.

SUNLU Filament Dryer S4, four-spool · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.6 / 5 · 150 ratings

5 stars78%78%
4 stars14%14%
3 stars2%2%
2 stars2%2%
1 star4%4%

Customer feedback describes the dryer as performing well and considers it worth the purchase price, with drying capability highlighted. The reported comments also include a claim that it can process up to 4 kg at once, which is consistent with the listing’s four 1 kg spool capacity. These are customer perceptions, not independent performance verification. Aggregate ratings are mostly five-star, but a smaller share are low-rated, so experiences are not uniformly positive.

Positive themes

Customers report positive impressions of performance, filament drying and value for money.

Frequently asked questions

How many spools does the SUNLU S4 hold?

The listing claims it can handle four 1 kg filament spools simultaneously.

Does the S4 control humidity automatically?

The listing describes Mode 2 humidity control in a 30%~50% range, with drying stopping below 25%. These are manufacturer claims, so check that the stated mode and thresholds suit your needs.

How quickly does it heat?

The listing claims a 350W PTC heater reaches 50℃ from 25℃ in 30 minutes. Treat this as a listed claim rather than a guaranteed result.

What are the listed dimensions?

Product dimensions are listed as 21.1D x 21W x 21.1H centimetres. Separate package dimensions are also provided, so check the product measurements before planning its placement.