SCUBAPRO's best-selling air balanced second stage and its top-performing air balanced piston first stage is a match made in diver heaven. Well-known for its low work of breathing, year after year this combo has consistently ranked as one of the top-performing reg systems on the market. The MK25 EVO first stage lets you enjoy an ultra-fast breathing response, instant delivery of air on demand, great sensitivity and impressive airflow. The S600 delivers smooth and easy inhalation and exhalation while offering efficient user controls, including a powerful purge, an inhalation effort control knob and Venturi Initiated Vacuum Assist (VIVA). Together they provide a steady flow of air, regardless of depth, water temperature, or workload.
  - 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 smoothes out the   inhalation effort at varying depths and supply pressures.   
- Second stage’s rugged reinforced technopolymer case and   front cover with stainless steel frame looks good plus is extremely durable.     
- Metal valve housing (barrel) is able to withstand years   of aggressive diving.   
- User controls include a diver-adjustable inhalation   effort knob and Venturi-Initiated Vacuum Assist (VIVA) dive/pre-dive   switch.
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