Halcyon valves are designed so that they open easily under pressure and close bottles. Has an additional Teflon washer provides Halcyon cylinder valve. In addition, the Halcyon valves are also processed very expensive.
Double bottles with Halcyon valves, 232Bar, DIR-style with stainless steel clamps and Rubber's Knob,CE,Breathing Gas,
Scuba tank from the company Euro cylinder with a concave base, made of steel with Halcyon mono valve.