The UNISLDSHF19M Adjustable Sliding Rack Shelf from StarTech lets you add a vented, sliding shelf with cable management into a 4-post server rack or cabinet. The adjustable mounting depth design allows the shelf to be installed into server cabinets with mounting depths from 27.7 to 31.6". The sliding rails also offer a locking mechanism to stop the shelf from sliding out too far, or sliding back into the rack before maintenance is complete. Offering a weight capacity of up to 125 lb, this sliding rack shelf features a ventilated, cold-rolled steel construction for increased airflow and durability in your server room or wiring closet installations. For ease in routing cables neatly through your rack, a reversible cable management arm is included and can be attached to the back of the shelf, as well as an adjustable bezel to keep your equipment where you want it on the shelf.