The ProForm Spiky Massage Ball Set includes three different-sized balls with acupressure spikes to stimulate nerve endings and release muscle tension across the entire body. The varying sizes target different body areas: small for feet and hands, medium for calves and forearms, and large for the back and glutes. Made from durable, non-toxic rubber, the spikes provide firm yet comfortable pressure without bruising. An affordable and portable tool for daily self-massage and myofascial release.