Marine Type Approvals held for these valves: American Bureau of Shipping, Bureau Veritas, DNV,Germanischer Lloyd, Lloyds Register. Atmospheric discharge safety valves made of brass with stainless steel spring. Suitable for the protection of pressure tanks and systems for air and other neutral, non-poisonous and non-flammable gases which can be freely discharge into the environment. with twist-type lifting mechanism. Available models: 812/412 sGK. Available seals: NBR, FKM, PTFE. Available in 1/2” up to 2”. All models are also available in Stainless Steel: Series 412. Model 412 sGK