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ASUS · Micro-Tower · Tempered glass

ASUS A21 Black

Mini-ITX, Micro-ATX · A21 ASUS CASE/BLK

Quality
65
Quality / price
84
Max GPU
380 mm
Amazon
$70
ASUS A21 Black
View ASUS A21 Black Gallery in high resolution
$70
Available on Amazon Updated Aug 30, 2026 Prime FBA
Overall quality65.0
Quality / price83.6
Cooling support15
$70 on Amazon Case table Compare this case

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Written analysis

ASUS A21 Black at a glance

The ASUS A21 Black is a Micro-Tower chassis with a tempered glass side panel profile. Supported boards: Mini-ITX, Micro-ATX. Primary materials are listed as steel, plastic, glass.

Overall quality is 65.0, summing compatibility, cooling, storage, build quality, and connectivity. Max GPU length is 380 mm. Max CPU cooler height is 165 mm. Largest radiator support is listed at 360 mm.

Best fit: High-end long-GPU builds that need support for at least one 360 mm radiator; verify the listed radiator positions before planning a multi-radiator loop.

Cooling and front I/O

Front ports: 1 x Headphone 1 x Microphone 2 x USB 3.2 Gen1. Dust filters: yes.

Current value

At $70, quality / price is 83.6. Compare nearby cases of the same form factor below; clearance and panel type can outweigh a small quality gap.

Chassis data

Full specifications

Construction, clearances, cooling, storage, front I/O, and quality metrics in one technical sheet.

General

Manufacturer
ASUS
Case
ASUS A21 Black
Form factor
Micro-Tower
Side panel
Tempered glass
Launch price
—
Amazon price
$70
Amazon availability
Available
Price updated
Aug 30, 2026

Construction

Material
steel, plastic, glass
Color
A21 ASUS CASE/BLK
Side panel detail
tempered glass
Dimensions
220*430*465 mm
Weight
7.30 kg
PSU shroud
Yes
RGB lighting
No

Quality & value

Overall quality
65.0
Compatibility
14
Cooling support
15
Storage score
12
Build quality
14
Connectivity
10
Quality / price
83.6

Compatibility / clearances

Motherboard sizes
Mini-ITX, Micro-ATX
Max GPU length
380 mm
Max cooler height
165 mm
Max PSU length
210 mm
PSU form factor
ATX, SFX
PSU included
No

Cooling

Max radiator
360 mm
Fan support
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
Radiator support
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
Pre-installed fans
Not specified
Dust filters
yes

Storage & I/O

Drive bays
1 x 2.5" Bay 2 x 2.5"/3.5" Combo Bay
Expansion slots
4
Front ports
1 x Headphone 1 x Microphone 2 x USB 3.2 Gen1
USB-C
Not listed

Additional information

Also listed as
A21 Black

Amazon

Price history

Nearby quality

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Discussion

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Vendor copy

Amazon listing details

Marketplace feature text kept for reference. Structured specifications above are the source for scores and comparisons.

Hidden Connectors: ASUS A21 is compatible with BTF hidden connector motherboards to maximize clean cable management

Broad Compatibility: A21 supports up to 360 mm radiators, graphics cards up to 380 mm in length and CPU air coolers up to 165 mm in height

Capable Cooling: The front-panel mesh is 40% porous to maximize the balance of airflow, dust filtering and RGB visibility

Ample Cable Management: The A21 provides a compartment behind the motherboard that is 33 mm wide to keep your wiring tucked away and tidy

Color-coordinated Builds: ASUS A21 comes with color-coordinated black or white internal I/O cables to compliment your build theme

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