The 601 Series dual stage regulator is designed with beam-mode quality in mind and virtually eliminates atmospheric contamination during a cylinder change. Low-level moisture and hydrocarbon contents yield a more stable emission and higher resonator efficiencies. The CONCOA 601 Series regulator provides the lowest-in-industry permeation rates with a 1×10⁻⁸ scc/sec helium leak rate and an integral purge valve with minimal threaded connections.