Thanks for the concern olsaltydog, it actually operates the same as a Hawaiian sling. In this pic I did have a carry strap hanging on it which makes it look more confusing. It uses PVC piping as the launch tube and rubber bungie as the propellant mechanism. I've used this concept out west before and worked great. I'll post some more photos when I get a chance for you. Either way it'll be staying in the closet for a while since it's no good here!