TheSamsonSRK 19" universal equipment racks are available in four sizes to accommodate any rackmounted gear setup: 8-space (SRK8), 12-space (SRK12), 16-space (SRK16) and 21-space (SRK21). All the racks are 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 European screw thread sizes, with both sets of screws included.