ORIGINAL: racewayking
I have a simlar invention called the Ghetto Puppet Can. I have used it for a few years now, here is a picture of it for those who haven't seen it. No screwing into trees required and adjustable, portable and easy to make. I have killed my last four bucks using it.
I didn't even go to that much effort. I wrap 20 feet or so of fishing line around the can and put a rubber band on it.
If you get to apoint you want to use it that way stick the end of your pull up rope under therubber band and a piece of chewing gum over the hole. Lower it down where you want it and just lift the fishing lineand drop it back when you want a bleat.
Just a note. I got no problem with the product and it seems a fair price. I have been doing this for several years and I "can" attest to the effectiveness of having the sound on the ground. Especially if they are in close and ya just need one to move in to a clear place to shoot.
I'm just a tight wad who never thought of trying to patent or sell it.