Has anyone used these little things before ?

I might have thrown away 59 dollars yesterday, but I bought one for use
with my Hobie out back fishing kayak, this thing has a transducer that
has a float on it, and 30 feet of cable that can be thrown out from the
boat, pier, or bank, to look for fish and give the depth.

It uses four AA batteries, which is great for the little outback (no
huge heavy 12 volt battery needed) I will be using NiMh rechargibles in it.

ANyone with any experience with it that can share will be appreciated
--
Rodney Long,
Inventor of the Boomerang Fishing Pro. , Straight Up Hooks ,
Straight Up Lures, Mojo's Rock Hopper & Rig Saver weights,
and the EZKnot http://www.ezknot.com