Extra D-rings make it easier to tie gear in a raft or canoe or to add grab lines for safety. These D-ring patches are made of sewn and glued Hypalon and Neoprene. Smaller 4-1/2″ D-ring patch uses a 1″ ring secured by a length of 1″ nylon, also sewn to a base of raft floor material. Surface patches are Hypalon. Large patches are strong enough to be used as rowing frame tie-downs.