This is the XS Scuba Scuba Tank Rail Kit For Hold TanksFeatures: Each rail includes two end stoppers with thumb screws and stainless steel mounting screws Rails have a clear anodized coating to resist corrosion Fits older TR100 model Aluminum rails provide the best mounting option. By mounting to an aluminum rail, the tank holders can be easily slid in or out. The rails are available in two convenient lengths: a 2-foot version, which holds 2 tank holders or a 3-foot version, which hold 3 tank holders. Includes Rail only.