The Hollister Adapt Convex Barrier Ring can be used to secure the seal of the ostomy pouch, making sure that no output gets underneath. These barriers can be cut or stacked for a better fit to the pouching system. One box includes (10) 20mm convex barrier rings. - Convex. Flextend material. Opening: 13/16 inch (20 mm). Can be stretched to 1 inch (25 mm). Available in round and oval shapes. Adapt Convex Barrier Rings can be used to help prevent ostomy output from getting under the pouch seal. They may be cut or stacked together to help improve the fit of a pouching system and are available in round and oval shapes to accommodate a variety of stomas. Adapt convex barrier rings can be used to create round or oval convexity, deep convexity when applied to a convex barrier or flexible convexity when applied to a flat barrier.