A Relay Rack is a 2-post steel structure with EIA universal (square) mounting holes. Relay Racks are also called 2-Post Racks or Open Bay Racks. The vertical holes spacing on Relay Racks are standardized for mounting Telco, or computer / network equipment. The height of almost all rack mountable computer / network equipment products are built to accommodate these EIA standard rack units. Relay Racks can also mount cantilever shelving for other non-rack mountable equipment.