I have had the 3500 going on 2 months now , so far its is very dependable and hasnt missed a lick . Most of all when i recieved it i put a 2 hr. charge on it and both the transmitter and reciever have a full charge. The transmitter fits the hand perfectly took a couple of times to get where the button were located , but once figured it out its aperfect fit. Thanks Dogtra and Pete Fischer..