| Model | ASUS A21 Case (Black) |
| Motherboard Support |
Micro-ATX Mini-ITX |
| Drive Bays |
1 x 2.5" Bay 2 x 2.5"/3.5" Combo Bay |
| Expansion Slots | 5 |
| Front I/O Port |
1 x Headphone 1 x Microphone 2 x USB 3.2 Gen1 |
| Radiator Support (Front) |
120 mm 140 mm 240 mm 280 mm 360 mm |
| Radiator Support (Top) |
120 mm 140 mm 240 mm 280 mm 360 mm |
| Radiator Support (Rear) | 120 mm |
| Cooling Support (Front) |
3 x 120 mm 2 x 140 mm |
| Cooling Support (Top) |
3 x 120 mm 2 x 140 mm |
| Cooling Support (Rear) | 1 x 120 mm |
| Maximum CPU Cooler Height | 165 mm |
| Maximum GPU Length | 380 mm |
| Maximum PSU Length | 210 mm |
| Dimensions | 220*430*465 mm |
| Weight | 7.3Kg |