30-2210 Size / Shape: 6" W x 36" D / Half-Round Features: -Perfect for positioning, balance, postural and muscle re-education.-User can move from an easier to a more difficult roller.-Great tool for ankle stretching and knee rehabilitation.-Use half roll as rocker board by standing on flat side.-Diameter refers to the width of the half-round profile.-Strong enough to be used by large adults and active children.-Can be used alone or with other exercisers.-Foam rollers for washability, firmness, and durability.-Available in half-round and round. Options: -Available in 2 sizes: 6" W x 36" D and 6" W x 12" D.