Designed with two settings to ease tight muscles and stiffness in the neck and back MB2 Roller® helps stimulate circulation, increase mobility in the spine, and improve posture Double massage ball design with patented, layered EVA foam surface encourages blood and oxygen flow to keep muscles and fascia healthy Adjustable length can be locked for use on smaller muscles around the spine, or extended to target the larger muscles of the back Highly durable, water resistant, and easy to clean Dimensions: 9.5 x 4.3 x 2.6 inches Weight: 109g