This is the Poseidon Xstream 1st Stage G5/8" Black Regulator Features: Air, Nitrox, Trimix and Heliox DIN G5/8" connection 5 LP and 2 HP ports Weight (g): 750.00 Material: Black Chrome Plated Brass Construction The objective; design the most reliable first stage in the world. A patented ruby ball seal is automatically positioned by the floating seat which balances any upstream pressure equally with the pressure adjustment spring, maintaining the benefits of having a perfect ball as the sealing element without the risks that follow with incorrect sealing pressures. This makes the Xstream Range self-balancing, giving the same high performance, irrespective of the pressure in the cylinder. Added to this the range has a built in anti freeze protection in its construction. The TDA (Thermo Dynamic Antifreeze) ensures that the through-flowing water keeps the ice away, entirely without fluids or extra diaphragms.