The Pro-Tec 4.5" Orb Massage Ball Activate offers a portable and effective vibrating massager that helps promote recovery and relief for sore muscles. You can easily choose between 3 different intensities to match the level of soreness, and the USB rechargeable battery lasts around 4+ hours. Firm bumps on the exterior help generate greater myofascial release when rolling in targeted circles while rolling the length of a muscle helps promote both flexibility and recovery.