Lightweight high-performance second stage with a free-flow control. Also includes a heat sink and has and adjustable cracking pressure. This is very important in Octopus regulators, since the Pre-Dive position is much more resistant to Venturi-Free-flows that can sometimes result in significant air-loss during a dive. The F8 Octopus comes with a Yellow cover and 36' hose. Features New inhalation diaphragm provides superior tear strength and improved response time to breathing (super soft silicone molded over a low friction disk). Improved exhaust valve ensures dryness and a lower exhalation effort. Seat-saving orifice, compliments of Atomic Aquatics, retracts when not in use - extending the life of the breathing tube seat. (#5,803,073) Seat comprised of soft silicone molded over a metal insert to deliver the firmness required for an airtight seal while maintaining the necessary elasticity to prevent leaking. Redesigned front cover and inhalation effort control knob use co-molded components that provide the necessary grip, soft touch and ease of use. Available in several color kits Zirconium-plated inlet tube and heat sink for superior corrosion resistance. Redesigned heat sink dramatically increases surface area, aiding in the heat exchange necessary to avoid freeze-up. Co-molded silicone mouthpiece for better fit and less jaw fatigue Materials - Cover: TPU, Case: Nylon 12, Poppet Seat: 316 SS insert with silicone overmold, O-rings: Nitrile, Diaphragm: Elastomeric Polymer, Exhaust Valve: Silicone