... 2,30 technology patents 2,BV&CE Cheap!! Gas detector alarm system with shut off valve 1. FeaturesLightweight, low- ... 3.Solenoid enclosures High-quality plastic solenoid enclosuresDust-proof, water proof, explosion-proofDegree of protection is generally 4. ... appropriate qualifications, and install and accept in accordance with construction specifications of gas pipeline and requirement of manufacturers ...