In this post, I am going to provide an in-depth review of the Scubapro MK25 EVO/D420 Scuba Diving Regulator. Starting with the MK25 EVO first stage, its features and then the D420 second stage and why they make a great pair.
I like that engineers at SCUBAPRO follow a different approach for pairing the first and second stages. Each component is first evaluated separately to determine its unique strengths. Using that information, SCUBAPRO then curates distinct combinations that suit specific diving environments. The result is a diverse collection of systems made by divers, for divers.
Key Features
Price: $399
MK25 EVO-Cold Environments
The latest regulator innovation from Scubapro is the exclusive Extended Thermal Insulating System (XTIS). Available in the MK25/MK2 EVO first stages, XTIS ushers in a new era of cold-water protection for the industry. Combined with other advanced features, you’ll be equipped to go further than ever.
The MK25 EVO is built with highly technical internal components that are all designed to enhance cold-water breathing performance. These include a new spring insulating coating, a new body insulating bushing, a new antifreeze cap, and a bigger body and cap thread. Externally, supplementary fins have been added to the machined body to provide extra thermal exchange.
Like the standard MK25, the MK25 EVO also offers an external intermediate pressure adjustment for hassle-free maintenance, and two high pressure ports and five low pressure ports mounted on a swivel turret for convenient hose routing.
First Stage:
Designed to be the ultimate first stage for cold water or contaminated diving conditions.
NEW design makes it substantially smaller and lighter than the original MK19.
Air-balanced diaphragm delivers consistent and effortless airflow, regardless of depth, tank pressure, or breathing rate.
Environmentally sealed system prevents water and pollutants from fouling the inner mechanism.
NEW dry chamber is equipped with a double spring, making it more compact and reliable.
Two opposing high-pressure ports allow the first stage to be positioned either up or down, plus provide for an optimum hose/transmitter layout.
Swivel turret comes with four High-Flow LP ports plus one axial Super High-Flow LP port to maximise hose routing options.
Compact size, light weight and superb breathing performance continue in the best SCUBAPRO regulator tradition.
Ideal first stage for recreational, technical, professional and military divers.
Weight: INT 232, 885g; DIN 300, 665g
Airflow at 2900psi/200bar: (l/min/SCFM): >6,900/244
Intermediate pressure (psi/bar): 133-142/9.2-9.8
Scubapro has been the Leader in the Evolution of piston controlled first stages since its beginning; the MK25 EVO carries on this heritage with an array of patented features ensuring unfailing performance. The MK25EVO is a balanced piston first stage, Scubapro's absolute top performer. It is a superior regulator thanks to its ultra-stable intermediate pressure (IP) resulting in an extremely punctual and constantly high delivery of air. This means instant airflow at any tank pressure and water temperature for a real carefree dive. Air balanced, flow-thru-piston first stages with air balanced pistons deliver significantly more air to the second stage than any other first stage, while their performance is totally unaffected by the changing tank pressure. A balanced piston allows the use of lighter and more sensitive components, resulting in ultra-fast breathing response, instant delivery of air on demand, and extra high air flow, especially in low tank pressure ranges. The tired diver benefits from a smoother breathing regulator during the ascent or deco stop. Balanced piston first stages are the first choice of demanding sport divers and professionals. A balanced piston performs equally in warm and cold-water environments. The MK25 EVO has two opposite 7/16" threaded high-pressure ports (HP). The arrangement of high and low-pressure hoses is crucial to diving comfort. Two opposite HP ports allow for an individual positioning of the first stage (pointing up or down). This allows the diver to position the gauges either on the right or left side and increases the freedom of movement for head and neck. Multiple low-pressure ports (LP) - For ultimate freedom in the arrangement of LP hoses, the MK25 EVO accommodates five HF (High Flow) 3/8" threaded ports on a swiveling turret, which allows for 360° swivel of hoses. High flow ports deliver about 15% more air than conventional ports. Externally adjustable intermediate pressure- allows authorized Scubapro service technicians to quickly fine-tune and adjusts the first stage after maintenance without the need to disassemble it. Cold Water Diving conditions can be drastically different, including extreme cold water and outside temperatures, posing the possibility of a regulator "freezing". Therefore, resistance to freezing is imperative for the diver. The MK25 EVO regulator uses Scubapro's new Extended Thermal Insulating System (XTIS). The Scubapro MK25 EVO first stage regulator meets the new EN250-2014 requirements for cold water diving, CE approved for 3360psi (230 bars). This model goes even beyond this super stringent qualification and has successfully been tested in extreme cold diving conditions at less than 36°F (2.2°C). The freezing resistance has been increased by 30% over the previous MK25 regulator first stage. Scubapro has achieved this with some new design features. The new MK25 EVO has a proprietary thermal insulating coating on key internal components and an encapsulating main spring bushing that resist the cooling effect in previous MK25 first stage regulators, also as a specific anti-freezing measure; Scubapro engineers have designed a patented finned cap with additional body fins for the MK25 EVO first stages for optimal-cold water diving. The fins (ribs) of the XTIS act as a radiator to increase the surface area of heat transfer from the water to warm up the internal parts that have been drastically cooled down by the gas pressure drop. The new MK25 EVO has a bigger body cap, new body with insulating bushing and ribs, new antifreeze cap patented isolation system with all internal parts fully insulated to dramatically improve cold water performance. This system now gives the diver superior cold-water performance, equal to that of Scubapro's MK17 first stage. Now you have the option of a high-performance flow through piston design, with a high level of performance in cold water. This is the answer for those divers who demand a high level of performance for cold water environments. The MK25 EVO is manufactured from marine grade chrome plated brass and offers a balanced composite/stainless steel flow-thru piston that would make any diver proud. It demonstrates Scubapro's dedication to quality and creating positive diving experiences.
More information on the: MK25 EVO
Key Features
D420-Balanced Valve
With the introduction of the 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 MK19 EVO balanced diaphragm first stage to create 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.
Second Stage:
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.
NEW 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.
NEW 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.
CE certified according the latest EN250A European Standards for all diving conditions, including extreme cold water.
Weight (without mouthpiece): 216g.
Airflow at 200bar: 1800 l/min – 64 SCFM.
The Scubapro D420 second stage regulators 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 3/8" threaded 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. Regulator weighs 40.8 oz. (1,157 g), is Nitrox compatible up to 40% oxygen and comes with an owner's manual.
More information on the: D420
Conclusion
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.
More information on the: Scubapro MK25 EVO/D420
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