"The Original Worm is the portable, full body massage roller that combines the benefits of therapy balls with a foam roller. The Worm’s specially designed (4) neoprene encased, solid rubber massage balls target 4x the body’s surface area. These massage roller balls will provide trigger point release to combat stiffness, pain and stress in muscles and joints. An easy to use, easy to carry, self massage tool."
The 6.3 consists of (4) balls that are a bit smaller and firmer than the 7.0. Gets into the tight spots. More intense than the 7.0.
The 7.0 cm consists of (4) solid rubber balls. Larger and slightly less firm than the 6.3. Great all around massage that covers more surface area than the 6.3.