Features: ALTERNATIVE TO OEM RAIL KIT: Provides a sturdy replacement for Lenovo/IBM System x3250 x3550 and x3650 M5 rail kits fitting standard 19" EIA-310 racks^^VERSATILE RACK COMPATIBILITY: Works with both 2 Post and 4 Post racks with adjustable mounting depth between 3"-30" (76.2 - 762 mm) supporting square round and threaded