Lian Li and DAN Cases have once again partnered to create a mid-size offering, and this time around it’s the B4-mATX, which can be oriented either horizontally or vertically. Lian Li and DAN Cases previously developed the A3-mATX-26.3L in 2024, which provided PC enthusiasts with a relatively low-cost option for smaller builds while also supporting behemoth-sized graphics cards along with a multitude of cooling options. Now, on its 2nd anniversary, the two case manufacturers have collaborated to create the B4-mATX, a slightly smaller 21.3L chassis supporting a dual-orientation configuration.
“Build like never b4!”
– Lian Li
Similar to their previous collaboration, this new case offers options for builders to use Mini ITX components such as smaller motherboards and PSUs or standard sizes. This time around, there are a few new design improvements, such as a rotatable power connector, a reversible rear fan bracket to provide more room inside the case, and the ability to build in either vertical or horizontal orientation. The B4-mATX also comes with 2x 120mm slim fans pre-installed and supports up to 1x 360mm AIO.
B4-mATX 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.
- Supports both horizontal and vertical layouts.
- Optional Vertical AeroDeck adds up to 3 × 120mm or 2 × 140mm fans for GPU cooling.
| Product Name | B4-mATX Mesh / B4-mATX Wood / B4-mATX Vertical AeroDeck |
| Model Number | B4X / B4W (Mesh) | B4X-WD / B4W-WD (Wood) | B4-1X / B4-1W (AeroDeck) |
| Color | Black / White |
| Dimensions (DxWxH) | 406.95 x 191 x 207.5mm (Chassis) | 407 x 191 x 41.2mm (AeroDeck) |
| Volume | 21.3 Liters |
| Material | Steel 4.0mm (Mesh) | Steel 4.0mm + Wood, Walnut or Beech (Wood) | Steel 4.0mm + Tempered Glass + Wood, Walnut or Beech (AeroDeck) |
| Motherboard Support | Micro-ATX / Mini-ITX |
| Expansion Slot | 4 |
| Storage | Front: 2.5″ SSD x 1 Bottom: 3.5″ HDD x 1 or 2.5″ SSD x 1 |
| GPU Length Clearance | 358mm (Max) |
| CPU Cooler Height Clearance | 162mm (Max) | 168mm (without side fan bracket) |
| PSU Support | ATX (Under 140mm) / SFX |
| Radiator Support | Side (With SFX PSU): 360 / 280 / 240 Side (With ATX PSU): 240 |
| Fan Support | Top: 120mm x 2 (Pre-installed) Side (With SFX PSU): 120mm x 3 or 140mm x 2 Side (With ATX PSU): 120mm x 2 or 140mm x 2 Front (With SFX PSU only): 120mm x 1 Bottom: 120mm x 3 or 140mm x 2 Rear: 120mm x 1 |
| Included Fans | Top: 120 x 120 x 15mm Slim Non-RGB Fan x 2 |
| Dust Filter | Bottom: Dust filter x 1 |
| I/O Ports | Power Button x 1 USB 3.0 Type-A x 2 USB 3.2 Type-C x 1 Audio x 1 |
| Warranty | 1-Year |
Prices range from $69.99 to $89.99 depending on color choice, and an optional mATX AeroDeck accessory is another $29.99. The B4-mATX launches today on Newegg and Amazon and will be available at 9 am EST.
B4-mATX Mesh Black: https://www.newegg.com/p/pl?d=9SIAFSTKV38658​
B4-mATX Mesh White: https://www.newegg.com/p/pl?d=9SIAFSTKV38657​
B4-mATX Wood Black: https://www.newegg.com/p/pl?d=9SIAFSTKV39355​
B4-mATX Wood White: https://www.newegg.com/p/pl?d=9SIAFSTKV39356​
B4-mATX Vertical AeroDeck Black: https://www.newegg.com/p/pl?d=9SIAFSTKV38659​
B4-mATX Vertical AeroDeck White: https://www.newegg.com/p/pl?d=9SIAFSTKV38656​
B4-mATX Mesh Black: https://www.amazon.com/dp/B0GX5DM6KB​
B4-mATX Mesh White: https://www.amazon.com/dp/B0GX5HP57Y​
B4-mATX Wood Black: https://www.amazon.com/dp/B0GX5D2FHW​
B4-mATX Wood White: https://www.amazon.com/dp/B0GX552844​
B4-mATX Vertical AeroDeck Black: https://www.amazon.com/dp/B0GX5FZTYC​
B4-mATX Vertical AeroDeck White:Â http://www.amazon.com/dp/B0GX53GPYL