This is the Zeagle Envoy/RaZor II Scuba Diving Regulator Features: Compact First-Stage/Valve Design Great for Stage Bottle or Redundant Air Supply System Nitrox Ready to 40% Out-of-the-Box Owner&';s Manual Includes Filling Adapter: Allows RaZor to Fill Tank w/Yoke Filling Whip Weight: 2.04 lbs. (925 g) First Stage Regulator: Zeagle RaZor High Performance Porting Non-Balanced Flow-by Piston Design 1&';st Stage/Valve Threads Directly into Standard 3/4-14 NPSM Scuba Cylinder Combination Saves Space & Increases Efficiency Ideal Where Weight & Space Are Critical One 7/16-20 UNF Threaded High-Pressure Port Four 3/8"-24 UNF Threaded Low Pressure Ports Multiple Hose Routing Options Chrome Plated Marine-Grade Brass Second Stage: Zeagle Envoy Pneumatically Balanced Downstream Demand Valve Lightweight, Compact and Comfortable Venturi (Free-Flow) Control Resistant to Free-Flow On-the-Surface Incredible Smoothness and Ease of Breathing Underwater Hose: 3/8" Threaded 36" (91.44 cm) Length Materials: Brass, Flexible & Ridged Thermoplastics, Elastomeric Polymers and Silicone Rubber "