Universal 19" Fit: This 1U 4-post server rack mount shelf is designed to fit 19in server racks and cabinets,fixed surface depth of 27.6in,adjustable mounting depth from 19.7 to 37.4in,according to the depth of the rack Sturdy and Durable:Constructed with SPCC commercial cold rolled steel, this fixed rack mount shelf supports up to 242lbs,especially for heavy IT equipment like tower server, UPS,NAS,amplifier and so on