All Preston pet products are made with durable nylon webbing. Collars and harnesses feature Delrin Acetal side release buckles for ease of fastening and separating and solid nickel plated āDā rings for strength. The collars are easily adjusted for length and are available in 10 sizes. Harnesses are available in two styles and 14 sizes. All Preston Leads use nickel plated swivel snaps. Collars, leads, and harnesses are 100% guaranteed for materials and workmanship.