The most common technical objections to the use of ordinary SCUBA valves with pure oxygen are: (1) too rapid a speed of opening and (2) chrome plating of the surfaces in contact with high pressure oxygen that are subject to friction or impact. The DGX Premium O2 valves are designed to answer these two specific objections. but otherwise similar to Nitrox Ready valves. For more information please read DGX Premium O2 Valve Differences.