The Junction strip is the connector for people that prefer to use round-wire for wiring their dollhouse. This unit has the same jack for the power supply plug and a fuse but also an on/off toggle switch and a set of 12 connection blocks to wire individual lights or rooms. Each block is numbered 1 through 12 and is marked with a + and a - for each set of lead wires to be connected from each light or circuit. The toggle switch on the circuit board turns on and off the entire set of blocks. As with the power connector, you need to select the size fuse to be included that matches the size power supply you are using. In other words, if you have a 2-amp power supply, you need a 2-amp fuse. Dimensions: 3.5" x 1.25" x 1.25"