The diameter of our replacement solar light is 8.1cm on the top and the bottom base diameter is 6.8cm. Please check your solar light size compatibility in advance. It takes 6-8 hours to charge, then it can work for 8 hours at night. Please turn on the button on the top before charging by sunshine or good daylight. It contains Ni-MH-AA battery with 600mAh/1.2V, and polysilicon efficiency of the solar panel is 25%. The LED chip is located at the bottom of the solar replacement top, provides soft warm light in the dark, 7 lumens. The solar covers are very suitable as a replacement for solar sprinkler lights and also for most solar lanterns, solar lights replacement fixtures. Please place the round solar panels in direct sunlight for best performance. But remember, dont place it in a place full of artificial light (the light sensor is too sensitive and will turn off the solar lamp).