With a ball joint that allows them to quickly be folded in. The Folding Bar End Mirror has a beautiful case mirror backing plate and the arms are one-piece, eliminating screws and mirrors vibrating loose. The nylon swivel allows just the right amount of tension to be maintained for easy adjustment. Dimensions: 3-5/16"Dia. x 9/16"D. Stem Length: 2-1/2". Fits 7/8" handlebars only. 3-5/16" dia. x 9/16" D