This Handy Adapter allows you to attach a Mini Pony bottle Gauge to the end of a High Pressure Hose. Inline Gauge Adapter is a great item for a Low Cost, Low Profile Pressure Gauge for Stage Bottles or Redundant Air Supply set ups. Adapter allows Inline (180°) connection with the HP Hose. Inline Adapter is made from Chrome Plated Brass for Durability and Long Life. Inline Adapter comes equipped with an Air-Spool with Viton O-rings so it's Nitrox Compatible.