This depth adjustable fixed rail kit contains two, 48,3 cm ( 19 inch ) to 78,7 cm ( 31 inch ), depth adjustable rails that mount Compaq rack-mountable servers, storage boxes, UPSs, and Compaq networking products in third party racks. The Depth Adjustable Fixed Rail Kit also allows for most third party rack-mountable products to be mounted in Compaq Racks. The depth adjustable fixed rails have a maximum weight capacity of 300 lbs.