The units sold by scotty are a 20 year unchanged design. I mean tubes and relays. the new units are made by the same company only for the 21st century. by using computer boards and prosessers they have lowered the price in half, cut the size in half and and made a better unit. I can't wait to get one. I have fished in lakes with the old units and the units that come on the cannon down riggers dig -a -trolls and they make a huge differance. some times if the fish are really on the cable they will not see your lure 10 ft behind the ball but will put their nose on the wire and follow that around.