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. The 8″ model has a 2″ plated steel ring held by a crow’s foot of 2″ nylon, sewn to a circle of heavy raft floor material and glued to the back of the patch. Surface patches are Hypalon. Large patches are strong enough to be used as rowing frame tie-downs.