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Black micro-ATX tower with mesh front panel and tempered glass side panel

ASUS

ASUS A21/BLK// Micro ATX PC Case Black

SKU CH-13PC-JADJY MPN A21/BLK//

A micro-ATX chassis of steel, plastic and tempered glass with a 40% porous front mesh, room for 360 mm radiators, 380 mm graphics cards and 165 mm CPU coolers, plus a 33 mm rear cable compartment

  • Max graphics card length380 mm
  • Housing materialSteel / Plastic / Tempered Glass
  • Supported motherboard sizesMicro ATX / Micro ATX (Back Connect) / Mini ITX
  • Dust filteringBottom / Top
  • 3.5-inch internal bays2
  • 2.5-inch internal bays1

Model A21 (Black)

  • Clean cable management with BTF hidden-connector motherboard support
  • 33 mm rear compartment keeps wiring tucked away and tidy
  • 40 % porous front mesh balances airflow, dust filtering and RGB visibility
  • Supports 360 mm radiators, 380 mm graphics cards and 165 mm CPU coolers
  • Black internal I/O cables match your build theme

Compact Micro ATX Chassis

The ASUS A21 is a Micro ATX case built from steel, plastic and tempered glass in a black finish. It accepts Micro ATX, back-connect Micro ATX and Mini ITX motherboards. The design targets builders who want a smaller footprint without sacrificing component clearance or cooling headroom.

Mesh Airflow and Cable Management

A front mesh panel rated at 40 percent porosity balances airflow, dust filtering and RGB visibility. Dust filters sit at the bottom and top. The rear cable compartment measures 33 mm wide for tidy routing. Color-coordinated black internal I/O cables match the theme. Front I/O supplies two audio jacks and two USB 3.2 Gen 1 ports.

Cooling and Component Limits

The case fits graphics cards up to 380 mm long and CPU air coolers up to 165 mm tall. Radiator support reaches 360 mm at the front and top, plus 120 mm at the rear. Fan mounts allow three 120 mm or two 140 mm units at front and top, plus one 120 mm rear. Two 3.5-inch and one 2.5-inch drive bays are available. The power supply compartment accommodates units up to 210 mm long.

How it compares

Measured against everything we stock in Tower & Desktop PC Cases, at today’s prices. Recalculated every night.

Price $50.99
Cheaper than about 90% of the 1,468 comparable items (median $100.99).
Max graphics card length 380 mm
Lower than about 62% of the 894 comparable items (median 400 mm).

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Specifications

Product
Brand nameASUS
Model nameA21/BLK//
Part number90DC00H0-B08000
Product typeMicro ATX
Product colorBlack
Storage
3.5-inch internal bays2
2.5-inch internal bays1
Ports & slots
Expansion card slots5
Front panel ports2 x Audio, 2 x USB 3.2 Gen 1
Size & build
Max graphics card length380 mm
Housing materialSteel / Plastic / Tempered Glass
Dust filteringBottom / Top
Fan mounting optionsFront: 3 × 120 mm / 2 × 140 mm
Top: 3 × 120 mm / 2 × 140 mm
Rear: 1 × 120 mm
Product dimensions18.3 in × 8.7 in × 16.9 in
Product weight18.52 lb (8.4 kg)
Shipping weight8.39 kg
Package size508 × 508 × 279 mm
Compatibility
Supported motherboard sizesMicro ATX / Micro ATX (Back Connect) / Mini ITX
Radiator supportFront:120 mm / 140 mm / 240 mm / 280 mm / 360 mm
Top: 120 mm / 140 mm / 240 mm / 280 mm / 360 mm
Rear: 120 mm
CPU cooler height limit165 mm
PSU length limit210 mm

Other versions of this model

5 more in the same range

Questions about this item

What USB standard do the front ports use and what is the practical speed limit?

The front panel has two USB 3.2 Gen 1 ports, which operate at up to 5 Gbps in practice.

What motherboard form factors and clearance dimensions does the chassis accept?

It fits Micro ATX, Micro ATX Back Connect and Mini ITX boards, with 380 mm GPU length, 165 mm CPU cooler height and 210 mm PSU length limits.

How are the dust filters removed for cleaning and which step is often missed?

Bottom and top filters slide out; the top filter is often forgotten because it sits under the removable panel.

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