The lightweight, simple, compact R2XR first stage is a classic downstream (aka "flow-by") piston design by Mares XR. The R2XR has four standard size low pressure 3/8-inch ports and one standard size high pressure 7/16-inch port. This regulator has the typical BSP G5/8 DIN connector that will fit 200 Bar and 300 Bar valves. One of the low-pressure ports now includes the Mares dynamic flow control (DFC) system to provide a constant inter-stage pressure during inhalation with gas flow unaffected by depth, tank pressure, or breathing rate. Tested with oxygen, the Mares R2XR now also includes their Auto Sealing Technology (AST) that stops moisture and contaminating agents from entering the interior of the first stage, as can happen during the surface interval when the regulator is being moved between tanks or post-dive when the regulator is rinsed.

Mares also offers this in a version in Europe with a green color bumper, however it also has an incompatible M26X2 fitting. Our US version has black color accents, but IS oxygen service and otherwise identical except that it has the standard BSP G5/8 DIN connector that will fit 200 Bar and 300 Bar valves. The US version of the R2XR is NOT compatible with the M26X2 Nitrox/Oxygen valve outlet mandated ONLY in the European Union by the EN 144-3:2003 standard.