D-ring curb bitD ring curb bit Jump'In Composition: D ring bit with 90 mm rings and 17 mm thick cannons made of German Silver (65% copper, 23% zinc, 12% nickel) a relaxing and solid alloy. Effect: D ring bits give better direction and is a great alternative to full cheek bits. The cheek pieces can be fixed in the pass of each ring for more fixity in the horse's mouth. Tips: the cannon of the curb bit gives the possibility to the horse to take a good tension on it.