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White mesh compact PC case, 21.3L, horizontal or vertical orientation, two 120mm fans visible

Lian Li

Lian Li B4W 21.3L mATX PC Case White Mesh

SKU CH-W29X-M6BN1

A 21.3-litre small form factor case for Micro-ATX builds with full mesh panels, horizontal or vertical orientation, and room for 358.9mm GPUs plus 360mm AIO cooling

  • Motherboard CompatibilityMicro-ATX
  • Power Supply MountedTop and Bottom
  • ColorWhite
  • Case MaterialSteel 4.0mm
  • TypeATX / Micro ATX Mid Tower
  • Front PortsUSB 3.0 Type A x 2, Power Button x 1, Audio x 1, USB 3.2 Typ

Option White Mesh Panel

  • Compact 21.3L footprint fits mATX builds in tight spaces
  • Horizontal or vertical orientation adapts to any desk layout
  • Full mesh panels and pre-installed 120mm fans deliver strong airflow
  • 358mm GPU clearance and 166.5mm CPU cooler height support high-end hardware
  • 360mm AIO compatible with SFX PSU or ATX PSU up to 140mm

Compact 21.3L mATX Chassis

The Lian Li B4W is a 21.3-litre small form factor case built for Micro-ATX motherboards. It accepts graphics cards up to 358.9 mm long and CPU coolers up to 166.5 mm tall. The chassis is constructed from 4.0 mm steel and weighs 13.45 units. Two pre-installed 120 mm slim fans provide immediate airflow.

Horizontal or Vertical Builders

This case suits users who want a compact mATX system that can sit horizontally or vertically on a desk. Builders needing support for larger E-ATX boards, radiators thicker than 360 mm, or power supplies longer than 140 mm should consider a larger enclosure. The mesh panels prioritise airflow over silent operation.

Pre-Installed Fans and Flexible PSU Mount

Two 120 mm slim fans are fitted at the factory, giving a working cooling baseline without extra purchases. The rotatable AC inlet and dual top or bottom power supply positions let builders route cables cleanly in either orientation. Front I/O includes USB 3.0 Type A, USB 3.2 Type C, audio and power button.

Highlights

  • Compact 21.3L footprint fits mATX builds in tight spaces
  • Horizontal or vertical orientation adapts to any desk layout
  • Full mesh panels and pre-installed 120mm fans deliver strong airflow
  • 358mm GPU clearance and 166.5mm CPU cooler height support high-end hardware
  • 360mm AIO compatible with SFX PSU or ATX PSU up to 140mm

Specifications

Motherboard CompatibilityMicro-ATX
Power Supply MountedTop and Bottom
ColorWhite
Case MaterialSteel 4.0mm
TypeATX / Micro ATX Mid Tower
Front PortsUSB 3.0 Type A x 2, Power Button x 1, Audio x 1, USB 3.2 Type C x 1
120mm Fans2
BrandLIAN LI
SeriesB4
ModelB4W
Max GPU Length358.9MM
Max CPU Cooler Height166.5MM
Weight13.45

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Questions about this item

What motherboard form factor must I already have for the B4W 21.3L case to work?

You need a Micro-ATX motherboard; the chassis is built around that form factor and will not fit standard ATX or Mini-ITX boards.

Will my existing ATX power supply fit alongside a 360 mm radiator in this case?

An ATX PSU up to 140 mm deep is supported, but a 360 mm AIO is only guaranteed with an SFX power supply due to internal clearance limits.

How can I verify the pre-installed 120 mm fans are spinning correctly after I build in the B4W?

Connect the fan headers to the motherboard, power on, and confirm rotation visually through the mesh panels or via fan-speed readings in BIOS or monitoring software.

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