Specification NotesValves are manufactured in accordance with BS 5154 PN40 for series A ratings. Design incorporates Duplex Stainless Steel S32205 plug type disc retained on stem by a threaded ring. The body seat is screwed-in stainless steel ring. Sizes 1/4" to 2" have a union bonnet and sizes 21/2" and 3" have a bolted bonnet. This valve is not suitable for use on group 1 gases or unstable fluids, as defined by the Pressure Equipment Directive 2014/68/EU. Valves having ANSI threads also generally conform to MSS SP-80.