After being totally disgusted & frustrated i couldnt get the damn cap back on , I asked my wife to get her little hand in there. while I was near cussing out the manufacturer, she said it felt like there was a spring when she put the battery in & pressed down-so thats how to get cover on. You must push & hold down & then turn (and have a screwdriver with perfect fit or youll strip it) She did it in about 7 seconds....