19in Vented Adjustable Depth Sliding Server Rack Cabinet Shelf. This Adjustable Depth Sliding Server Rack Shelf offers a simple way to install non rack mountable equipment into a server cabinet or open server rack. The shelf features a highly ventilated, cold-rolled steel shelf on two locking adjustable rails which allow the shelf to be installed into a cabinet or rack with a minimum mounting depth of 20in (510mm) to a maximum depth of 38in (974mm). The locking feature locks the shelf 3/4 of the way out, preventing the shelf from accidentally falling out of the rack or sliding back in before maintenance is complete.