Well I thought I would give y'all an update. We went over to Camping World and bought the RM 7735. We opened the box an the battery was totally dead. No problem, charge it. Yes problem, once it was charged the screen locked upwhen I unplugged the power. The On/Off button would not work, nothing. I even checked it for a lock, no joy. Back to the store this am, got another unit. The battery was also dead so I plugged it into power in the truck and headed home. The map actually worked going home but when I unplugged it at home the screen locked up again. Plugged it back in, no joy unplugged no joy, back to CW. Two or three people at CW tried to get it to work without sucess. I came home with a full refund. I am NOT a happy camper.