The MK11 first stage is the perfect choice for the recreational diver who wants the advantage of a diaphragm first stage for use in cold or temperate waters. Diaphragm-based first stages are environmentally sealed so that water cannot enter the internal mechanism. Bearing in mind that regulators generate temperatures as low as 22°F (-5.5°C) due to the incredibly fast-moving air and pressure drop involved, it is imperative that the sensitive moving metal parts avoid contact with extremely cold water or debris. Therefore, diaphragm first stages have been the preferred choice of cold-water divers and those working in contaminated or muddy water. Scubapro diaphragm first stages feature balanced technology and are packed with patented features, resulting in ultra-fast flow to the second stage on demand and fantastic overall performance. The streamlined body of the MK11 first stage is constructed from machined marine-grade chrome-plated brass. The MK11 features a balanced diaphragm for peace of mind with its smooth breathing mechanisms and peak performance that doesn't diminish as your tank air pressure changes. This first stage is available in DIN configuration. This first stage comes standard with the Thermal Insulation System (TIS), which prevents your first stage from freezing and malfunctioning in cold water conditions. Additionally, its super-balanced diaphragm first stage design offers improved breathing performance at greater depths. The first stage regulator is equipped with two HP ports with 7/16" threads and four LP ports with 3/8" threads. Two of the LP ports are high-flow ports (HFP) for easier breathing during demanding dives. The regulator weighs 470g. The regulator does not include a low-pressure hose.