The Seasonic ARCH Series creates an interplay and connection between two important pillars or product group integration; the Seasonic CONNECT Module and the Seasonic SYNCRO Q70 Case. Timeless appearance, modern design, and user-friendly functions make this case a logical choice for users, who want convenience, easy assembly, and hassle-free cable management with the Seasonic CONNECT.

  • Dimensions (D x W x H): 448 x 215 x 482 mm
  • Form Factor: Mid Tower
  • Materials: Steel, Plastic
  • Side Panel Type: 4 mm Tempered Glass Side Panel
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Ultimate Cable Management

The seamless integration with the Seasonic CONNECT keeps both sides of the case neat and tidy.

Easily Accessible I/O Panel

Easy access to control buttons and connectors (USB Type-C included).

Versatile Cooling Options

With 3 pre-installed 120 mm fans (two in the front and one in the back), the ARCH Q503 allows for expansion and customization.

feature summary

  • Compatibility with Seasonic CONNECT for ultimate cable management
  • Stylish tempered glass side panels on both sides
  • Sturdy steel plate (0.7 mm) construction for durability and noise dampening
  • Pre-installed 120 mm fans (two in the front and one in the back)
  • Captive thumb screws to prevent them from getting lost
  • Easy access to control buttons and connectors (USB Type-C included)



Case Specifications    
Dimensions (D x W x H) 448 mm (D) x 215 mm (W) x 482 mm (H)  
Form Factor Mid Tower  
Materials Steel, Plastic  
Side Panel Type 4 mm Tempered Glass Side Panel  
Compatibility and Clearances    
Mainboard Support Extended ATX, ATX, Micro ATX, ITX  
Maximum Motherboard Size 305 mm x 277 mm  
Maximum PSU Length 230 mm  
Maximum CPU Cooler Height 165 mm  
Maximum GPU Length 380 mm  
Access and Control    
Power 1  
Reset 1  
USB 3.0 2  
HD Audio IN 1  
HD Audio OUT 1  
USB 3.1 Gen 2 Type-C 1  
PCIe and Slots Drive Bays    
PCIe Slots 7  
3.5" HDD Bays* 3  
2.5" SSD Brackets 3  
Fan Capacity 120 mm 140 mm
Front 3 2
Top 2 2
PSU Shroud 2 0
Rear 1
Dust Filter Top / Bottom
Radiator Capacity    
Front Up to 360 mm  
Top Up to 280 mm  
Rear Up to 120 mm  
Parts and Accessories    
Fans Included 2 x 120mm Fans in Front, 1 x 120mm Fan in Rear  
Seasonic CONNECT 1 (80PLUS® Gold 750 W or 650 W)
3-to-1 PWM fan splitter (pre-installed) 0
3.5" HDD Drive Bays* 0  
2.5" SSD Brackets 1  
Removable Dust Filters 2  
Cable Management Cover 0  
PSU Shroud 0  
Motherboard and 2.5" SSD Screws 17  
Motherboard Standoff 8  
3.5" HDD Screws 8  
Power Supply Screws 6  
Reverse Fan Screws 0  
Cable Tie 8  
User Manual 1  
Fabric Gloves (Pair) 0  
Soft Cloth 0  
ARCH Q503 2 Years

* 3.5” HDD bays can be used for 2.5” SSD.