This mature version of AIR KICKS fits adult-sized men that weigh between 99 and 199 lbs. with shoe sizes ranging from four to 13. They have an adjustable split-foot plate to ensure the perfect fit for everyone. Powered by patented Jumping Jax technology, AIR KICKS Anti-Gravity Boots feature heavy-duty, interchangeable T-springs that transform downward energy into a bouncing motion that is gentle on joints, muscles and bones. The boots’ high-traction tread is safe to use on any indoor or outdoor surface. AIR KICKS fit over normal running shoes.