Folbe Boat Fender Hanger Adjuster Clip (Sold in Pairs) - Fits 7/8" (22 mm) Rails - White Snaps On! Twists Off! Easiest boat bumper adjustment. Works best with 5/16-7/16 lines ( 8mm-11mm). Excellent marine material is very durable and won't discolor. Works with virtually any type of line.