personnel electrolysis [SEP] i read the reviews so i took a gamble on it i read the instructions first trying to get the back open for the battery was too hard one side just would not release after the struggle of getting the battery in the first push of the slide button and it came off i did not try to glue the button back on for me this works good on thin hair not so much for the thick hair this is time consuming i got this so i may use in between my electrolysis appointments this could have stayed in the store