Miller electric flashback arrestors, it is designed to help prevent accidents caused by reverse gas flow or flashbacks built-in check valve protects against reverse flow brass construction for long life 100% tested for reliability and performance color coded by gas service for easy identification. capacity: welding: 3/8" cutting: 12" maximum inlet pressure: acetylene: 15 psig other fuel gases: 22 psig oxygen: 145 psig, hose size: 9/16" - 18 std.