Samson SRK21 Universal Rack StandPerfect for holding musical equipment, networking gear, servers and more, The Samson SRK21 is constructed of heavy-duty steel with fully enclosed side panels as well as both front and rear rack rails. Their side panels also feature perforations for passive ventilation. The racks are set upon four 3" (75mm) casters with locking fronts that can handle a weight capacity of up to 300lb (450lb without casters). each rack comes with a blank, single-space panel. Lastly, their unique steel support bar design allows these racks to be compatible with either the U.S. or metric screw thread sizes, with both sets of screws included.Reliable Hardware Company RH-RMSET-25-A 25 Sets of Rack Rail Screws and WashersRack Rail Screw and Washer.