The 12V Easy Twist Cable connector system is easy to use, simply select the lights you want and count up the wattages of all your chosen lights. Now you can decide which transformer to use, 20W, 60W or 105W. Add up the wattages of the individual lights and determine the size of transformer you need, the wattage of the transformer needs to be larger that the total wattage of your lights. Measure the distance from the light furthest away to the transformer this determines the length of your mains cable, 10 metres or 15 metres. Then place the mains cable and the cable of the lamp inside the connector, place the cap on and then twist together to make the connection.