Heck, what about 4? Just kidding, I use a couple steel electrical outlet boxes filled with duct seal, about $1.29 for the boxes, and another $4 for the duct seal. Shot it with my 40+ fpe Talon and also with my Sumatra and my Career....never bounced back and no holes in the back. The only downside of duct seal is that you eventually have to clean it out or replace it...., but you can put a boatload of pellets into it before that happens. I also have a cheapo Beeman pellet trap with the deflector plate idea. Works good for my 500 fps match rifle, but it makes a loud clank when you shoot it.