Features:

• 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.

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.

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.

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.

• DIMENSIONS (DxWxH): 420 x 191 x 288mm
• MOTHERBOARD SUPPORT: Back-Connect: NO / Micro-ATX, Mini ITX
• STORAGE: Front: 2.5” SSD x 1 Bottom: 3.5” HDD x 1 or 2.5” SSD x 1
• CPU COOLER HEIGHT CLEARANCE: 162mm (168mm without side fan bracket)
• PSU SUPPORT: ATX (Up to 140mm) / SFX
• RADIATOR SUPPORT: Side (With SFX PSU) 360mm / 280mm /240mm Side (With ATX PSU): 240mm

FAN SUPPORT

• Top: 120mm x 2 (Pre-installed)
• Side (With SFX PSU) 120mm x 3 / 140mm x 2
• Side (With ATX PSU): 120mm x 2
• Front (With SFX PSU ONLY): 120mm slim fan x 1
• Bottom: 120 mm x 3 / 140mm x 2
• Rear: 120 mm x 1