Tripp Lite's 4POSTRAILKIT adjustable rackmount shelf system supports heavy UPS systems in 4 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 inches. Includes mounting hardware compatible with square-hole racks. Also compatible with other heavy pieces of networking or power protection equipment with 17.5 inch wide rectangular chassis."Maximum Load Capacity: 250 lbPackage Contents: 4POSTRAILKIT Rack Mount Rail Kit Includes: Pair of expandable L bracketsAttachment hardwareCompatibility: UPS SystemPower Protection Equipment with 17.5 wide rectangular chassisGreen Compliant: YesGreen Compliance Certificate/Authority: RoHSLimited Warranty: 5 YearPackage Contents4POSTRAILKIT Rack Mount Rail Kit Includes: Pair of expandable L bracketsAttachment hardware"