"Smaller than a foam roller and larger than a tennis ball, it's the best of both worlds! The Pro-Tec Athletics 4.5"" Orb Extreme Massage Ball provides an aggressive deep tissue self-massage that allows you to easily and effectively target the areas you need it most. Use it on your IT band, hamstrings, quads, calves and more. You'll enjoy decreased muscle fatigue, increased flexibility and enhanced performance. Plus, the uber-portable size of the Pro-Tec Athletics 4.5"" Orb Extreme Massage Ball makes it easy to throw in a bag or purse and take with you anywhere you go!"