Click Dry Lining Pattress Boxes - Click WA087P, Single gang pattress box from Click, ideal for use when flush fitting 13A sockets or plate switches into hollow, dry lined (ie plasterboard) partition walls. When the boxes are fitted into a suitably sized hole, side mounted lugs are extended sideways behind the plasterboard, and when the socket or switch is fitted and the fixing screws tightened, the whole assembly is clamped securely to the board. Click WA087P SB619 Dry Lining Pattress Box - Single