I purchased one and have used it a couple of times. It works okay for mapping the depths, but I wouldn't recommend it for evaluating the fish population. I believe the depths are shown to the foot and not to the tenth or hundredth of feet.

The only complaint I have is the range. It seems to not work when the remote transducer is more than 30' (10 yards) or so from the wrist receiver. I understand the models other than the wrist band type allow for a little more range reception.

Hope this helps.