Report "I am replaceing batteries in a friends shaver. I have done several replacements on my own Norelco's. (All the way back to when they had sub 'C' batteries in them.Don't know what piece of plastic you are refering to. There is one large black plastic plate between the batteries & switch with a square hole in it. It is locked in place rock solid. Did the piece of plastic you are refering to, sit in that square hole, & maybe (when he took it apart), it unknowingly fell out & he lost it? Thanks for your help... J.P. HAM radio operator, WB7PZW"