Scubapro MK25 EVO/S600 Scuba Diving Regulator

Scubapro MK25 EVO/S600 – Balanced Piston First Stage and Air-Balanced Second Stage Set

The Scubapro MK25 EVO/S600 is a complete regulator system pairing Scubapro's highest-performing first stage with a fully adjustable, air-balanced second stage.

If you are an advanced or highly active recreational diver who dives regularly, dives cold water, or simply refuses to compromise on breathing performance, this system is built for you.

If you are newly certified and looking for your first regulator, this is not where to start. The MK25 EVO/S600 is a premium, full-featured system. Its strengths are real, but so is the investment it represents, and a diver who is still building experience will not yet feel the difference that justifies it.

The MK25 EVO First Stage

The MK25 EVO uses a balanced flow-through piston design. Here is what that means in practice: because the piston is balanced, the intermediate pressure it delivers to your second stage stays consistent regardless of how much air remains in your tank. You get the same breathing effort at 200 bar as you do at 50 bar.

The flow-through piston design is particularly relevant in cold water. Water flows through the first stage body and around the piston, which sounds counterintuitive until you understand the physics: it prevents the pressure differential that can cause ice to form and lock the piston open, resulting in a free-flow. Scubapro has reinforced this with their Extended Thermal Insulating System (XTIS), which adds another layer of freeze resistance. The MK25 EVO meets EN250-2014, the European cold-water performance standard, so this is not a marketing claim. It is a tested and certified rating.

Port configuration gives you real flexibility in hose routing:

• Five low-pressure ports, threaded 3/8", for your second stage, BCD inflator, drysuit inflator, and any additional low-pressure accessories
• Two high-pressure ports, threaded 7/16", positioned opposite each other for left- or right-side gauge or transmitter placement

The turret swivels, which means you can adjust hose angles after the first stage is on the tank. This matters when you are configuring a complex hose setup or diving with a sidemount or backmount rig where routing clearance is tight.

The first stage body is chromed brass, with a composite and stainless steel piston. Brass is denser than some materials used in travel-oriented regulators, and the total system weight comes in at 35.9 oz (1,018 g). That is not a light setup. If travel weight is your main concern, this is worth knowing before you buy.

The S600 Second Stage

The S600 uses an air-balanced valve. This means the valve mechanism is designed so that the ambient water pressure does not increase the effort required to crack it open. The result is a consistent inhalation feel across depth, without the slight stiffening some unbalanced second stages show as you go deeper.

Two controls let you tune the breathing character to conditions and preference:

• Adjustable inhalation resistance: a dial that lets you increase or decrease how easily the valve opens. Divers who want a very free-breathing feel can open it up; those who want to reduce the risk of free-flow at the surface or in surge can tighten it slightly.
• Venturi dive/pre-dive switch: set it to pre-dive at the surface to prevent accidental free-flow when the second stage is not in your mouth, then switch to dive once you are underwater to allow the Venturi effect to assist inhalation.

The case is techno polymer, a reinforced plastic that keeps weight down without sacrificing durability. The valve housing is chromed brass. An extra high-flow exhaust valve clears exhaled gas efficiently, which reduces the back-pressure you feel on exhalation, particularly at depth.

Who This System Suits Best

The MK25 EVO/S600 performs at its best when conditions are demanding. Cold water, deep recreational dives, high workload dives, or situations where consistent intermediate pressure matters most are where this system earns its position.

It also suits divers who plan to own and maintain a regulator for many years. Scubapro's service network is wide, and a chromed brass first stage with a stainless steel piston is built to be overhauled repeatedly.

If your diving is warm water, moderate depth, and low frequency, a simpler system will serve you well. The MK25 EVO/S600 does not breathe better than you need it to on a 18-metre Caribbean reef dive. Its engineering is aimed at the diver who pushes conditions or simply wants the ceiling removed.

A Quick Spec Summary

The MK25 EVO/S600 is a mature, well-engineered system with a clear purpose. If your diving demands consistent high airflow, reliable cold-water performance, and a second stage you can fine-tune to your breathing style, this setup delivers all of that without compromise.