With the introduction of he new D420. Scubapro engineers have combined the iconic design of the original D-Series second stages with the latest advances in breathing performance technology.  They then teamed it with the new MK 19 EVO balanced diaphragm first stage to create a 21st century smooth, natural breathing regulator.  The new D420 features a brand new balanced valve inside a housing supported fy a full metal structure.  Called the Progressive Flow Control Valve, it is able to deliver abundant airflow for the best breathing perforamance 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 inclues a switch on the top of the casing with a thumb tab for adjusting the directino 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 compact, lighweight MK19EVO, with its environmentally sealed sysem, dry ambient pressure chamber plus user-friendly LP port swivel turret, this regulator system is uniquely well-suite to handling cold waer and the harsh diving conditions often encountered by technical divers.  This makes the MK 19 EVO/D420 more tech-driven than the MK 25EVO/D420, while serving avid divers and Scubapro brand enthusiasts everywhere.