Fits any 4 Post rack - Non-ball bearing, slide rails - Square, round, threaded hole compatible - Adjustable mounting depth - HP rail kit not required - Mounting Depth: 18.5" - 32" (469.9 mm - 812.8 mm) Alternative to HP DL380 Gen 8, DL560 Gen 8, Gen 9 & Gen 10 rail kit - Mounts DL380 Gen 8 & Gen 9 in 4Post racks - Mounts DL380 Gen 8 & Gen 9 in any 2Post Relay Rack Fits any 2 Post rack - Center mounts in 2 Post rack - Works with 3" - 6" uprights