Middle Atlantic RK-GD16 This RK-GD16 Smoked Tempered Glass Door (16) for RK and BRK Series Racks from Middle Atlantic is a front door that is designed to work with RK and BRK series laminate cabinets. This door features a smoked tempered glass front panel that allows you to freely view your equipment even when the door is securely shut. This model is designed to work with 16U racks.