Your body isn't flat. Your roller shouldn't be. Get the roller made to fit your body. With six sizes and two densities, there is a knot out for every need and every body. The product's unique shape matches the curves and pockets of your body, effectively working out adhesions and knots., the longer length of the Maxx roller provides a more stable surface during use., the Maxx M firm is great for:, lower back, upper trapezius, subscapular release, lower legs, knot out rollers are:, highly effective mobility and recovery tools., easy to take with you anywhere., durable and easy to clean and disinfect., regular use of the knot out roller helps:, increase mobility and flexibility, reduce muscle discomfort and improve tissue quality, improve recovery from workouts, size: 2.9 in. Dia. X 11 in. LONG, weight: 2.2 lb., materials: balls - solid natural rubber, sleeve - polyolefin, warranty: 1 year