This article covers Montech AIR 903シリーズ.

Overview

The Montech AIR 903 MAX is a mid-tower case designed for high airflow and E-ATX motherboard support. It comes with multiple 140mm fans pre-installed, so you can start building immediately without additional cooling purchases. The tempered glass side panel lets you show off your components and RGB lighting. Positioned as an upper mid-range case, it targets gamers and PC enthusiasts who want excellent thermal performance without sacrificing expandability. With support for E-ATX motherboards and room for multiple storage drives, the AIR 903 MAX offers flexibility for future upgrades. The focus on airflow — via a mesh front panel and large-diameter fans — makes it suitable for high-power components that generate significant heat.

Compatibility Guide

The case supports E-ATX (up to roughly 272mm width), ATX, Micro-ATX, and Mini-ITX motherboards. Power supply mounts at the bottom and accepts standard ATX units. Multiple 2.5-inch and 3.5-inch drive bays are available. Since exact clearances for GPU length and CPU cooler height are not confirmed from official sources, measuring your components or checking Montech's support page is recommended before assembly.

Product Info

Released around 2023, the Montech AIR 903 MAX is priced around ¥56,143 on Japan (as of August 2026). It occupies a solid mid-to-high-tier position in the market, offering E-ATX compatibility, pre-installed 140mm fans, and a tempered glass panel — features often found on more expensive cases. Cooling is air-based, with multiple fans included to ensure good out-of-the-box thermal performance.

Best Use Cases

First-time gaming PC builder: With pre-installed fans and tool-free drive bays, assembly is straightforward. E-ATX support means you can choose larger motherboards without worrying about fit. Airflow-focused enthusiast: The mesh front and large 140mm fans deliver excellent ventilation, ideal for high-TDP CPUs and GPUs in a gaming or workstation build. Builder wanting expandability: Room for multiple drives and support for large radiators (though not officially confirmed) make this case future-proof for upgrades. Not suitable for: Those who prefer a compact or Mini-ITX-only layout, or who need a case under ¥30,000.

Things to Consider

Official specifications for maximum GPU length, CPU cooler height, and radiator support are not fully documented in the available sources. Measure your components or contact Montech before finalizing a build. While the case is labeled E-ATX, some oversized E-ATX boards (304×330mm) may not fit — verify the motherboard dimensions. At roughly ¥56,000, it is slightly more expensive than some competing mid-tower cases, but the bundled fans and tempered glass panel justify the premium. ## FAQ
Q: Will an E-ATX motherboard definitely fit? A: It supports E-ATX up to about 272mm width. Larger extended ATX boards may not fit. Check your motherboard's exact dimensions against the case's motherboard tray specifications. Q: Can I install a 360mm liquid cooler radiator? A: The official radiator compatibility is not confirmed in available sources. The top panel likely supports 240mm or 360mm radiators, but verify the clearance with Montech before purchasing. Q: What power supply size works best? A: Standard ATX power supplies fit without issue. A fully modular unit is recommended for easier cable management, but any ATX PSU will work.

Product Disclosure (Amazon)

  • Manufacturer: Montech
  • Seller: ネットショップOaR
  • Fulfilled by: ネットショップOaR
  • ASIN: B0C98RRPXL
  • Note: This article covers a manufacturer-made product based on Amazon listing details.