Oxy/Fuel regulator-mount Pair Pack. Flashback arrestors and reverse flow check valves provide additional protection against flashbacks. Victor recommends the use of these devices whenever possible. Victor add-on flashback arrestors contain both a reverse flow check valve and a flashback arrestor. Due to the high flow requirements of Victor Heavy Industry torches, it is important to use flashback arrestors that have sufficient flow capacity. It is important to understand the difference between reverse flow check valves and flashback arrestors. Reverse Flow Check Valves: Helps prevent the reverse flow of gases from traveling past the check valve. Flashback Arrestors: Prevents a flame from traveling past the flashback arrestor in the event of a flashback.