R2 Nikos; the only regulator with a MARES piston first stageand the DFC system. Its simple construction and extraordinary toughness are matched by outstanding performance, even at great depths. Another record by MARES.  Its surprising breathing sensivity is obtained through the use of the D.F.C. system for the first time in a piston first stage. This is coupled with optimized cross sections and flows with an oversize "high flow" hose. Nikos second stage is used in this model; it is equipped with a tangential vane to guarantee a controlled Venturi effect. A bellows diaphragm is also provided to optimise air flows, together with oriented water ducts.