Features - As an extra security FR-18, 63 flashback arrestor should be mounted on the pipes at all acetylene gas central installations. It is designed to arrest the flame and cut off further flow of gas. In case the flame is not arrested the temprature will rise inside the Arrestor melting the soft soldring. A spring loaded valve will then close the outlet and further supply of acetylene will stop. - Working pressure : 1.5 bar - Mounting : FR-18, 63 is always mounted directly behind the central regulator and in the service line at the point of entry to each locality.