TRIPP LITE's 4POSTRAILKIT adjustable rackmount shelf system supports heavy UPS systems in four post rackmount applications. Two included pairs of expandable "L bracket" mounting rails offer front to rear support rackmount UPS systems. Pair of expandable "L brackets" adjust to any setting between 20.5 and 36 in. Includes mounting hardware compatible with square-hole racks. Set of temporary placement pegs enables simple single-person installation by allowing the rails to be held in place while attachment hardware is installed. Also compatible with other heavy pieces of networking or power protection equipment with 17.5 in wide rectangular chassis. Supports up to 250 lb