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Product information
From the manufacturer
About this product
- Compact 21.3L mATX case with broad compatibility.
- Supports M-ATX / Mini-ITX, 358mm 4-slot GPUs, and 140mm ATX PSUs.
- Supports up to 360mm radiators with SFX PSU, or 240mm with ATX PSU.
- Up to 168mm CPU cooler clearance, or 162mm with side fan bracket.
- Includes 2 pre-installed 120 × 120 × 15mm slim top fans.
- Supports up to 9 fans across top, side, bottom, rear, and front.
- Removable top bracket simplifies CPU 8-pin routing and fan setup.
- Removable front bracket allows easier large GPU installation.
- Supports both horizontal and vertical layouts.
- Optional Vertical AeroDeck adds up to 3 × 120mm or 2 × 140mm fans for GPU cooling.
Build like never B4
Co-developed with DAN Cases, the B4-mATX’s modular design unlocks versatile build possibilities. With multiple color, panel, and layout options, plus an optional accessory, it adapts to a wide range of styles.
Compact Design, Broad Compatibility
With a compact 21.3L volume, the B4-mATX delivers impressive hardware compatibility, supporting M-ATX motherboards, 360mm AIOs, 140mm ATX PSUs, and up to 358mm 4-slot GPUs.
Minimal Design,Multiple Styles
The B4-mATX offers a clean mesh panel for an airflow-focused look or a real wood panel for a warmer, refined setup. Both support front-to-back airflow, balancing cooling performance with a streamlined exterior.
Vertical Mode,Maximized Desk Space
The vertical layout improves desk space efficiency by up to 30%. Integrated rear feet allow quick and easy switching between different usage modes.
Rotatable AC Power Connector
Designed for both horizontal and vertical configurations, the rotatable AC inlet adapts to your setup. Face it outward for convenient cable access, or rotate it inward in vertical mode to avoid clearance limitations.
REVERSIBLE Rear Fan Bracket
The rear fan bracket features a reversible design for greater layout flexibility. It can be installed outward to create more clearance for liquid cooling, or inward to position the fan closer to the CPU airflow path and improve CPU air-cooling performance by up to 1°C.
Recommended Liquid Cooling Configuration
The B4-mATX supports 360mm and 280mm radiators with up to 52mm total thickness.
Extra Intake, Better Cooling
Supports a 120 × 120 × 15mm slim front fan with an SFX PSU and GPU under 343mm long, helping improve intake airflow.
PRE-INSTALLED 15MM SLIM FANS,
Flexible Airflow Design
Two pre-installed 120 × 120 × 15mm slim fans on the top provide enhanced cooling performance. Operating up to 1800 RPM, they are daisy-chained to reduce cable clutter.
Flexible GPU & Fan Support
Supports up to 358mm long 4-slot graphics cards. Bottom fan support varies by GPU thickness: 2.5-slot GPUs support 25mm fans, 3-slot GPUs support 15mm slim fans, and 3.5-slot or thicker GPUs do not support bottom fans.
Easy GPU Installation
The removable front fan bracket lets large graphics cards slide in from the front side of the chassis for a smoother installation process.
Pre-Installed
GPU Anti-Sag Bracket
Built to handle GPUs up to 4 slots thick and 358mm long, the case comes equipped with a dedicated anti-sag bracket to ensure stability and prevent sagging.
Modular Design, Easier Installation
Tool-less removable panels offer quick and easy access for installation and cable routing, while a removable bottom dust filter helps maintain a clean system.
Removable Top Fan Bracket
The removable top fan bracket provides easier access for routing and managing CPU 8-pin cables, while also making it simpler to configure the front-top fan as intake for air-cooler setups.
Easier Cable Management
Cable tie points around the PSU and top brackets help secure CPU 8-pin and PSU cables for a cleaner, more organized build.
In vertical mode, a removable bracket and rotatable cable guide work together to route cables cleanly through the bottom of the case.
Flexible Storage Support
Supports 1 x 2.5” SSD at the front, with space at the bottom for either 1 x 2.5” SSD or 1 x 3.5” HDD.
ACCESSIBLE CONNECTIVITY
The I/O layout keeps essential ports easy to reach in both traditional and vertical layouts, with a high-speed USB Type-C port supporting up to 20Gbps transfer speeds.
In Collaboration with DAN Cases
Co-developed with Daniel Hansen of DAN Cases, the B4-mATX combines flexible modularity with LIAN LI’s precision craftsmanship in a compact form.
Hard Compatibility
Tool-less removable panels offer quick and easy access for installation and cable routing, while a removable bottom dust filter helps maintain a clean system.
Product details
35
| Bottom fans diameters supported | 120, 140 mm |
|---|---|
| Capacity | 21.3 L |
| Depth | 420 mm |
| Fan speed | 0 - 1800 RPM |
| Form factor | Mini Tower |
| Front fans diameters supported | 120 mm |
| Height | 288 mm |
| Material | Steel |
| Maximum airflow | 64.2 cfm |
| Maximum air pressure | 2.4 mmH2O |
| Maximum CPU cooler height | 16.2 cm |
| Maximum graphics card length | 35.8 cm |
| Maximum PSU length | 14 cm |
| Noise level | 30.3 dB |
| Number of 2.5" bays | 1 |
| Number of 3.5" bays | 1 |
| Number of bottom fans supported (max) | 3 |
| Number of front fans supported (max) | 1 |
| Number of rear fans supported (max) | 1 |
| Number of side fans supported (max) | 3 |
| Product colour | White |
| Rear fans diameters supported | 120 mm |
| Side fans diameters supported | 120, 140 mm |
| Side radiator sizes supported | 360, 280, 240 mm |
| SSD form factor | 2.5" |
| Suitable for | Gaming |
| Supported HDD sizes | 2.5, 3.5" |
| Supported motherboard form factors | micro ATX, Mini-ITX |
| Supported power supply form factors | SFX, ATX |
| Top fans installed | 2x 120 mm |
| Type | PC |
| USB 3.2 Gen 1 (3.1 Gen 1) Type-A ports quantity | 2 |
| USB 3.2 Gen 2 (3.1 Gen 2) Type-C ports quantity | 1 |
| Warranty period | 1 year(s) |
| Width | 191 mm |
Logistics
| EAN | 4718466023278 |
|---|---|
| Unit of measure | — |
| Weight | — |
| Dimensions | — |
| Dangerous goods | No |
Warranty
- 12-month warranty on everything we sell.
- Runs from the day your order is delivered.
- Faults under normal use are repaired, replaced or refunded.
Payment
- Visa and Mastercard, processed securely by Tyl by NatWest with 3D Secure.
- PayPal — your PayPal balance or a saved card or bank account.
- Clearpay, Klarna and Billie — pay later or in instalments, processed by Stripe.
- No surcharge on any payment method; refunds go back to the way you paid.
Spread the cost
- 4 interest-free payments of £18.99 with Clearpay. Learn more
- 3 payments of £25.32 at 0% interest with Klarna. Learn more
- Businesses: pay in 30 days on invoice with Billie. Learn more
Choose at checkout. 18+, T&Cs apply, credit subject to status.