I bought this for a BRK20 rack being used in a home audio system, mainly to block some of the fan noise from the amplifiers. It installs to swing from the left or right, and has a key lock if you need that. If you don't need or want the key lock feature, there is a supplied magnet to hold the door closed. Plastic pivot bushings press into pre-drilled holes in the rack top and bottom panels to act as bearings. The closed door is recessed slightly (about 3/8") and leaves a small gap (1/4" or so) around the periphery to allow air flow.Installation requires moving the front rack brackets back to different (pre-drilled) holes; space from the front bracket to the door (for air flow, equipment switches, lights, etc.) is then about 1". If you need more than that, you can move the front rack brackets back further, to the next set of holes (also pre-drilled).The result is a very presentable and professional looking assembly, suitable for home or studio use. Highly recommended.