Plug With Valve - Grey - C39.00.00011 . Regulators are "relieving" as standard. "Non-relieving" available upon request. 2. Regulators are available for use with water. Please state when ordering. 3. Standard regulation is 0-8 bar. Also available 0-2 bar, 0-4 bar, 0-12 bar. Lock-down rings are fitted as standard on all regulators and filter regulators.