Mares has incorporated top modern regulator technology into the 28XR-HR diving regulator. The first stage uses an innovative balanced diaphragm, which is operated by a double piston. AST - Auto Sealing Technology guarantees a perfect seal against the possible entry of sand or other particles, especially in cave diving or in polluted waters. The rotating swivel turret with a vertical low pressure port and 4 more low pressure ports makes it usable in all configurations. Its flexibility allows it to be used on double tanks and in stages and side mount configuration. The second stage has a techno polymer body which is simple and ultralight, providing excellent performance. A large side knob allows you to adjust breathing force, even when wearing thick neoprene gloves. The Mares 28XR-HR Side mount Regulator Set contains all the necessary hardware and accessories that a diver needs for a side mount breathing system.