The Dell PowerEdge R320, R420, R430, R620, R630, NX300, NX400, R230 Slide Rails can provide a stable, sturdy and easy-to-install sliding rail solution for Dell-compatible server racks. These slide rails are compatible with standard 19" EIA-310 server racks, and can work with either 2 post or 4 post models. In terms of server compatibility, the slide rails are designed for the Dell PowerEdge R320, R330, R410, R415, R420, R620, R630, R230, NX300 and NX400. 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.