MK25 EVO 1st Stage is one of the highest highest performance first stages available now, with a dramatically evolved balanced piston first stage with 30% increased freezing resistance, greater inhalation sensitivity for ultrafast breathing response, instant delivery of air on demand and extra high airflow no matter how cold the water temperature. The balanced piston design is more than capable of supporting a whole team of divers simultaneously without faltering. The sleek body has heat exchanging fins incorporated into its design to aid dissipation of the cold generated by the first stage as it works. The piston and main spring have been specially coated with an anti-freeze layer to improve cold water performance and reliability. The MK25 provides two high pressure ports and five low pressure ports (four around a swivelling turret and a high flow port of the very end of the turret).
Extended Thermal Insulating System, X-TIS, fully insulates the internal mechanism from the environment. A form of environmental seal the X-TIS improves cold water / freezing resistance without compromising piston breathing performance (patent pending).
The A700 2nd Stage features a full metal housing that is designed to offer excellent cold water performance as the metal construction allows the cold to be transferred to the surrounding water far quicker and more efficiently than normal plastic housings. The A700 allows the diver to independently adjust the venturi and inhalation resistance. The venturi control adjusts the flow of air within the housing, directly it toward the mouthpiece for optimal flow or toward the diaphragm to aid closing the valve. The inhalation control increases or decreases the tension on the valve spring, making it harder or easier to breathe (the default position is tuned to provide optimal performance).