These mosaic ball string lights feature dual power technology they require 1 x rechargeable battery and 1 x alkaline battery included to power the light when the rechargeable battery has less than 10 charge meaning that they stay on to be enjoyed for much longer thank standard solar string lightsr ideal for garden lighting all year roundr 1m lead cable from solar panel to the first light 31cm spacing between each led auto switch in at dusk dual power technology