# 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.

- [Original product page](https://bargainpostbox.co.uk/product/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)
- [View offer](https://bargainpostbox.co.uk/visit/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)
- Market: UK
- Language: en-GB
- Currency: GBP
- Brand: SUNLU
- Model: SUNLU Sécheur à filament S4
- Price: 84.98 GBP
- Previous price: 99.99 GBP
- Discount: 15%
- Price checked: 2026-11-12T17:36:33.165Z
- Rating: 4.6 / 5
- Reviews: 150

Prices and deal status are the latest recorded data, not a guarantee of availability. Confirm the price and availability with the store.

## 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℃.

## 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.

## 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

## Before you buy

- 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.

## 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.

## Customer feedback

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.

## Alternative options

- [Sovol Filament Dryer SH03, 85°C 3D Printer Filament Dryer Box for PETG ABS \| Upgraded 4-Spool Filament Dehydrator, Circulation Fans/Auto Moisture Removal/Auto Dry Mode for PLA PETG TPU ABS 1.75/2.85 mm](https://bargainpostbox.co.uk/visit/sovol-sh03-four-spool-filament-dryer)
- [SUNLU Official AMS Heater, Simultaneous Drying & Printing, 3D Printer Filament Dryer for AMS Gen 1, Smart Humidity Control, Heats to 70°C in 20 Min with 4-Spool Capacity](https://bargainpostbox.co.uk/visit/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)
- [Creality Official Space PI Filament Dryer, 3D Printer Filament Dryer Box with 360° Heating, Upgraded Filament Dehydrator Storage Box Support PLA ABS PETG TPU 1KG 1.75/2.85mm](https://bargainpostbox.co.uk/visit/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)
- [Creality Official Space PI Filament Dryer, 3D Printer Filament Dryer Box with Built-in Fan Filament Storage Filament Dehydrator for 1KG 1.75/2.85mm One-Key Setting for PLA PETG ABS TPU Nylon](https://bargainpostbox.co.uk/visit/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)
- [SUNLU Filament Dryer Box S2, Up to 70°C with 360° Surround Heating \| 3D Printer Filament Dryer Keeps Filament Dry During 3D Printing, Compatible with PLA/PETG/ABS/SILK/PA/PC, Black](https://bargainpostbox.co.uk/visit/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)
- [Creality Filament Dryer Box 2026 Upgraded, SpacePi SE Upgraded 65° PTC Heating with Fan, Dust & Moisture-Proof Storage, 3D Printer Filament Spool Holder, Dehydrator for 1.75mm/2.85mm PLA PETG ABS TPU](https://bargainpostbox.co.uk/visit/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)
- [Creality Filament Dryer, 4-Spool SpacePi X4 3D Printer Filament Storage Box, Dual Independent Heating Chambers Up to 85℃, Active Dehumidification, Power Saving for PLA, PETG, ABS, TPU, Nylon, etc](https://bargainpostbox.co.uk/visit/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)
- [SUNLU S2 3D Printer Filament Dryer, Filament Dry Box S2 with Airflow Fan, Reduce Moisture During 3D Printing, Filament Dehydrator 360° Surrounding Heating, SUNLU FilaDryer S2, Filament Holder, Black](https://bargainpostbox.co.uk/visit/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)

## Add-ons

- [Thlevel Humidity Meter Sensor Hygrometer Room Temperature Humidity \| for Greenhouse Basement 3 Pack](https://bargainpostbox.co.uk/visit/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)
- [wisedry Silica Gel Desiccant Beads Bulk Reusable with Color Indicating Orange to Green Bead Size 2-4 mm Rechargeable with 20 Pcs Organza Drawstring Bags - 3,6 kg \[ 8 LBS \]](https://bargainpostbox.co.uk/visit/sunlu-filament-dryer-s4-four-spool-b0cxtd88x2)

## Images

![SUNLU Filament Dryer S4, four-spool — 1](https://bargainpostbox.co.uk/i/kAWYNXMAUDHG55ssxkyJh6mknBN6I7u8911ZWTdbD6pVK1VSRA83QRY8eGUPxpZBfq93dpAC_un2BzSkQsEKYoQZQMceLeQfT16ci-PXWGbagWvooeOCm5KF.jpg)

![SUNLU Filament Dryer S4, four-spool — 2](https://bargainpostbox.co.uk/i/Yw67JUXd-yM3VVmkfGlbvPgZV5ZuurIKskf_WxQ5HmfB9WNNIDYu7VQmZnU8zVSVjVbhdKopmqizajP8Ye2Ukq2MOTf7ih5auGHcXxVLIouVCqfwAjuU5gVM.jpg)

![SUNLU Filament Dryer S4, four-spool — 3](https://bargainpostbox.co.uk/i/O3y1OGtKE01ohI7YSISl666FyRPb1KhdU3PML3R4QbT24lVdxJxL-vGpFzUfReU61H3dVLbrmC4KPadS6C4wHegsSQZvQKj-0OOiyt_QM77_KNKiQc0WBr07.jpg)

![SUNLU Filament Dryer S4, four-spool — 4](https://bargainpostbox.co.uk/i/pulxFIi4usLqfDKyms67lGtpdMK9swFcLbQQZzP5hAE5E04QK9JSRmcj0du-YksRZYyzLYDAgNSSkBLg4RzMnlcfCotQ6m_Tb24Gi4uE2vIobyYHFHsGzy5r.jpg)

![SUNLU Filament Dryer S4, four-spool — 5](https://bargainpostbox.co.uk/i/eW6e_GDbF4lCoMEkIb2vBAjZZ7N4yGPLZet6PGqu-eWgPnS8c9o6k_bKIE54wMN28sbCIBOKWiTexXH3ySSZHUrsMNTszeCcA6yTy1msC8s59OSOTzgTUWDD.jpg)

![SUNLU Filament Dryer S4, four-spool — 6](https://bargainpostbox.co.uk/i/LYGiz8pk7WXnWEVoR__4bW9AMOWkWXVduxN1KnbGuSd2p6iK1LiTkeZElmwYmTCslG98PmI_iJc7TQcrLMHAqNOhMKKx1ambVSJAntWDMW9e5opu8JDQmBun.jpg)

![SUNLU Filament Dryer S4, four-spool — 7](https://bargainpostbox.co.uk/i/jnFz663YE7t4D9WwDdeuOdmH3iDudCjJV-X5UJTM_OHxwA5nxvt0PMVd0NDh6INK4lKOS7jVzv6J_LrbPwQQhjw2k0aSKASkM_iobobOibfwORJuktgwkswu.jpg)