The MB1® Massage Ball provides direct deep tissue compression for fast relief of aches, pains and muscle fatigue in small areas. It can be used on any surface, so you can roll anytime, anywhere.    Features Ideal for targeting small muscles such as calves, piriformis, and pecs Encourages blood and oxygen flow to enhance overall movement, range of motion and performance Foam surface is easier to clean and more hygienic than cloth 6.60cm diameter,  Backed by 1-year manufacturer's warranty   Check out this video: