This Telco Rack Shelf is compatible with most 19" EIA Standard Telco Racks. The 29" Telco Rack Shelf has a 300 lb (136 kgs) equipment capacity and will support a wide variety of electronic equipment. Electronic Devices up to 29" (736 mm) deep can be supported on the Relay Rack Shelf. This 2 Post Rack Shelf comes with flanges up, flanges down or with one flange up and one flange down. See product names below to make the shelf distinction when making your online purchase. Transport and Seismic options are available for this Relay Rack Shelf if the installation requires.