This is the Zeagle F8 Octo 2nd Stage Scuba Diving Octopus Safe Second 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 Lightweight high-performance second stage with a free-flow control. Also includes a heat sink and has and adjustable cracking pressure.