but the 150!! I figured using a 250 was overkill as you don't need pinpointing when water hunting. Just "X" the coil over the target and start scooping. I used a 3500 Otterbox, removed the back half of the housing, soldered a battery pack from Radio Shack onto the board, drilled holes for the coil connector and Garrett Headphones(no exposed speakers), sealed it up with marine silicone and hit the water. Actually there was more to it than that, but basically that was it. You might want to build an extension cable as mine is out to it's limit and I would like to have a few inches more to move the box back. Skillet built me a straight shaft and that is a big improvement over the "S" shaft in the water. My Otter is really nicely balanced. I can pick it up by the hand grip with one finger and it just sits there, balanced.
The Ace in the water seemed to be energized!! I get way better depth in the water than on land. I've scooped some targets that took me many scoops down to get them up. Now all of this is in fresh water, not sure how it would act in salt.