This control box is for dividing a track or accessory circuit into 4 different circuits, each with two connections. For example, 4 storage sidings in the same track circuit or 4 users in the same accessory circuit can be turned on and off. The control box comes with 8 sockets on the back and a plug on one end and a socket on the other end. All of the connections are for the new plugs from the 71400 sets. 8 appropriate plugs included. Dimensions 80 x 40 mm / 3-1/8" x 1-9/16".