The RumbleRoller - The surface of the RumbleRoller contains 200 specially designed "bumps" that are firm but flexible, much like the thumbs of a massage therapist! The bumps are firmer than muscle tissue, but much softer than bone, so they deflect out of the way if they contact your spine or other bony protrusions. As you roll on the RumbleRoller, the bumps continuously knead the contours of your body, gently stretching soft tissue in multiple directions to help restore flexibility and bring relief to common types of muscular pain. The RumbleRoller was molded with an antimicrobial additive that stops the growth of bacteria so it can be used with multiple clients. The RumbleRoller is 31" x 6", water-proof and latex free.