Universal Rack Shelf. The Samson SRK 19"; universal rack shelves provide convenient placement and accessibility for your non-rackmountable gear. Available in two sizes (1-space and 2-space), these rack shelves are ruggedly constructed of cold rolled steel plates capable of holding up to 33 and 44 pounds of equipment respectively. While perfectly compatible with any standard equipment rack, the SRK Rack Drawers are ideal for use with the Samson SRK and SRK Pro Racks.