Just a light plastic baseball with holes in it.

You use a light plastic bat to hit. I had some 12 year old Pitching at me and he made the ball curve 3 feet. I was AMAZED that in 10 at bats, I struck out only once. The raised basketball goal robbed me of my best hit. It was HR bound. All my others were grounders. But like I said, I was THRILLED to hit it at all. It was sprinting / base running that did me in.