When you have chosen the lights you require from our low voltage Connect Go range, it is essential that a power source is purchased to power them. This D battery box (batteries not included) is manufactured specifically for use with this range & will power up to a maximum of 400 LEDs. Our medium battery box features a 30cm clear cable & boasts 4 different functions, which are listed below. Next to each function, you will find the maximum running time for each setting. This will, of course, vary depending on the brand of D batteries used: 1. On-Steady (1 week) 2. On-Twinkle (2 weeks) 3. Timer-Steady (4 weeks) 4. Timer-Twinkle (8 weeks) Each time you switch the lights on, the built-in memory chip will automatically select the last function used. The handy timer function means that you can leave the lights switched on; they will remain illuminated for 6 hours, before turning off for 18 hours & then turning back on at the same time as the previous day.