This is the Scubapro MK25 EVO/D420 Scuba Diving Regulator 1st & 2nd Stage

Features:

• Uniquely shaped fiberglass-reinforced nylon casing carries on the D-Series heritage with the latest advances in breathing performance technology.
• Air-balanced Progressive Flow Control Valve is able to deliver abundant airflow with a natural smoothness comparable to breathing on the surface.
• Dive/pre-dive system includes a switch on the top of the case with a thumb tab for adjusting the direction of airflow right out of the valve.
• Casing design features inner winglets that direct airflow towards the exhaust valve, creating a dramatic improvement in exhalation effort.
• Diaphragm is located in the lower section of the casing to take advantage of the pressure gradient in the upright position, making breathing even easier.
• Reversible hose attachment allows for either left- or right-side LP hose connections for maximum rigging flexibility.
• Large purge button is easy to reach and depress, with or without gloves.
• Exhaust tee is compact and efficiently deflects bubbles from the diver's view while enhancing ease of exhalation.
• Super-flow hose features an oversized bore that allows more air to flow on each inhalation.
• Compact Hi-Flow mouthpiece improves airflow as well as mouth comfort, fitting all mouth sizes, from largest to smallest.
• Air balanced flow-through piston first stage design delivers consistent and effortless airflow, regardless of depth, tank pressure, or breathing rate.
• Patented XTIS (Extended thermal Insulating system) fully insulates the inner mechanism from the environment, improving cold-water resistance by 30% 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.
• CE certified according the latest EN250A European Standards for all diving conditions, including extreme cold water.

Combining the iconic design of the original D-Series regulators with the latest advances in breathing performance technology, SCUBAPRO engineers have created a 21st century regulator in terms of quality, reliability, performance and style. The new D420 features a brand new balanced valve inside a housing supported by a full metal structure. Called the Progressive Flow Control Valve, it is able to deliver abundant airflow for the best breathing performance, with a natural smoothness comparable to what you might experience breathing on the surface. The uniquely shaped fiberglass-reinforced nylon casing is ultra-durable and allows the LP hose to be connected on either the right or left side for maximum rigging flexibility. A new dive/pre-dive system includes a switch on the top of the casing with a thumb tab for adjusting the direction of airflow right out of the valve. The highly efficient purge button is a technical jewel based on a new concept that gives the D420 its unique face. Teamed with the venerable MK25 EVO balanced piston first stage, this is a regulator system purpose-designed for today's avid divers and SCUBAPRO brand enthusiasts everywhere.