Here is a balance disc that you can use for stability and core training. The Smart Body Leverage Disc has a smooth surface to keep you comfortable as you perform rotational exercises. You can use this to perform squats and lunges. The Leverage Disc can is also useful for those of you who want to avoid knee pain during exercise.
The Smart Body Leverage Disc doubles as a seat cushion that relieves back, tailbone, and other sitting pains.