The Lenovo/IBM System x3250 M5, x3550 M5 and x3650 M5 Slide Rails can provide a stable, sturdy and easy-to-install sliding rail solution almost any server racks. Lenovo/IBM System M5 Slide Rails are compatible with standard 19" EIA-310 server racks, and can work with either 2 post or 4 post models. The device is designed to fit in racks using either standard square, round or threaded holes, and feature an adjustable mounting depth between 3” - 30" (76.2 - 762 mm). This rail kit is not a ball-bearing rail kit.