This is the Zeagle Onyx II Octo Scuba Diving Octopus Features: High Performance Octopus Regulator Pneumatically Balanced Downstream Demand Valve Lightweight, Compact and Comfortable Diver Adjustable Inhalation Resistance Venturi (Free-Flow) Control New Compact Profile Built-In Anti-Freezing Heat Sink Feature Cover: Flexible Thermoplastics Case: Ridged Thermoplastics Heat Sink: Anodized Aluminum Diaphragm: Elastomeric Polymer Exhaust Valve: Elastomer Mouthpiece: Silicone Rubber O-Rings: Buna-N Yellow Cover and Braided Hose for Easy Identification Hose: 36 (91.4 cm) with 3/8" Threads Zeagle&';s Onyx II Octopus Second Stage is lightweight, compact and comfortable, with diver adjustable inhalation resistance controls, free-flow control, and anodized aluminum heat sink built-in anti-freezing feature. Specific design changes have created a regulator that is resistant to free-flow on the surface yet has incredible smoothness and ease of breathing underwater. This pneumatically balance downstream demand valve second stage regulator is manufactured from flexible and ridged thermoplastic, elastomeric, polymer and silicone rubber."