Polyethylene foam rollers are perfect for positioning, balance, postural and muscle re-education, spinal stabilization, body awareness and coordination, and ranging and strengthening activities. Round rollers offer progressive exercise sequences - user can graduate from an easier (smaller diameter) to a more difficult (larger diameter) roller. Half round roller is a great tool for ankle stretching and knee rehabilitation. Diameter refers to the width of the half-round profile. The foam is strong enough to be used by large adults and active children. Foam rollers are available in 48", 36", 30", 24", 18" and 12" lengths and 3", 4", 6" or 8" diameters with either a round (circular) or half-round (semi-circular) profile. Polyethylene foam rollers are available with standard formula in white and blue. They are also available with anti-microbial additive, in beige. 6" x 36" and 6" x 12" half rollers available sliced or fully extruded so that the bottom has an integral skin. Choose the roller that is right for you! Full-Skin - White PE foam - 6" x 36" - Half-Round.