I got this and used it 2 times. Works great, now I'm in a cam boot and I just use that in the pool. I paid like $40 shipped, and it was worth it to me to pay $20 each time just to swim around and be off crutches for an hour or two. Its a size large half leg. Here is the web sight:
http://www.activeforever.com/p-1403-...oof-cast-cover

I tossed the original package, but it's basically a fancy rubber sock with a valve and a hand pump. I'd post in gear trade but if you gimpy you might not be looking for gear.