Can this case support a full-size ATX power supply, and are there any specific mounting requirements?

Yes, the case supports a full-size ATX power supply.

Questions & Answers: PC Test Bench Open Air Computer Case ITX UMATX MATX ATX Motherboard Chassis Aluminum Bracket DIY Bare Frame Support 120 240 360 Liquid Cooling

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PC Test Bench Open Air Computer Case ITX UMATX MATX ATX Motherboard Chassis Aluminum Bracket DIY Bare Frame Support 120 240 360 Liquid Cooling

Made of aviation magnesium aluminum alloy with sufficient thickness of 8mm (real thickness) by NC finishing,the surface is sandblasted and hard anodized, beautiful and generous.
Size:36x30x20cm;Applicable Mainboard: For ATX,Matx,UMATX and ITX motherboard
Supporting integrated water-cooled installation (120 240 360 water-cooled drainage).
Support HDD:2 and SSD:2;Support ATX power supply.Support 2 360 water cooling both install on the case;No limit for the length of the video card(when install CPU water cooling the limit for the length of video card is 28cm).
Open frame design, with good heat dissipation performance, bringing great using experience.And you can clean the dust on the PC case really easy too.