Asus 1U Rackmount Chassis Kit R10-A2P4 - Manual (Page 17)

2-5 ASUS R10-A2P4 1U rackmount chassis kit
2.3 Motherboard installation
2.3.1 Motherboard dimensions
This chassis kit supports an ASUS motherboard that measures 12 x 10.5
inches (30.48 x 26.67 cm). Motherboards of smaller sizes will fit into the
chassis. Refer to the motherboard user guide for more information on the
motherboard dimension and other system requirements.
This section only describes how to install a supported motherboard into
the R10-A2P4 chassis kit. Refer to the motherboard user guide for
instructions on installing specific motherboard components.
Make sure that the motherboard you intend to install to the chassis
does not exceed the maximum specified dimensions. Otherwise, it will
not fit into the chassis.