This is the Scubapro MK25 EVO DIN 300/G260 Scuba Diving Regulator

Features:

• Air-balanced flow-through piston in a chrome plated brass body provides constant and effortless airflow unaffected by depth, tank pressure, or breathing rate.
• Patented XTIS (Extended Thermal Insulating System) thermally insulates the inner mechanism from the environment, improving cold-water resistance and delaying ice formation in extreme cold-water conditions without compromising breathing performance.
• Anti-freeze protection radically increases breathing reliability when diving in the most extreme water temperatures.
• Two opposing high pressure ports allow the first stage to be positioned either up or down.
• Four high-flow and one axial super high-flow low pressure ports on a swivel turret maximize hose routing options.
• External intermediate pressure adjustment enables technicians to fine-tune performance quickly and easily.
• Air-balanced second stage valve smooths out the inhalation effort at varying depths and supply pressures.
• Rugged reinforced technopolymer design features SCUBAPRO's largest second stage casing and diaphragm for the ultimate in breathing sensitivity, regardless of position in the water.
• Metal components (inlet tube, orifice, inhalation control knob and hose connector) increase resistance to freezing when diving in extreme conditions.
• A diver-adjustable inhalation effort knob fine-tunes air delivery to suit changing depths, water conditions and personal tastes, and a Venturi-Initiated Vacuum Assist (VIVA) dive/pre-dive switch prevents free flows in cold water or when used as an octopus.

When you team SCUBAPRO's flagship first stage with a second stage engineered to excel in harsh conditions, you get a system that any recreational or technical diver can take on any dive, anywhere in the world, and be assured of rock-solid performance and reliability. The MK25 EVO/G260 is just such a system. The MK25 EVO delivers an ultra-fast breathing response, great sensitivity and extra-high airflow, making it the ultimate do-it-all first stage for all water temperatures. The G260 is the most imitated air-balanced second stage of all time. It features metal internal components and a left-right hose attachment option, making it a great choice for tech diving configurations and a consistent top-of-the-line performer.