SmartRack® SRCAGENUTS is compatible with all square-hole rack enclosure cabinets. Square hole hardware kit has 5 M6 cage nuts and 5 bolts to fasten equipment to square-hole rack-mount rails. * Square hole hardware kit - 5 each M6 cage nuts and bolts * Fastens equipment to square hole rack mount rails * Compatible with all square hole racks (EIA 31D)