Check the listing for details. Oxygen Torch Welding, Brazing TORCH End FLASHBACK ARRESTOR, w/barb fitting. "B". Condition: New. Listed at 9.95 USD. Oxygen Flashback Arrestor. Attach at the Torch. Add arrestor to your Torch, add the barbed fitting. Then add your hose using a hose clamp. Arrestor also has a check valve internally. Highest quality. 9/16 -18 threads, B Size. We also carry the acetylene arrestor, or by the set. Please check our listings on eBay. Never connect a torch to acetylene and oxygen tanks without installing a set of flashback arrestors. Without these safety devices, it is possible a flash can occur within the hose, and ultimately follow back into the tanks, causing an explosion. This would be an extremely rare occurrence, but flashback arrestors will make it a "never" occurrence. Check valves are only a first line of defense and may not ultimately stop a flashback. Only the flashback arrestors will. ISO 9001 certified factory. Thanks very much.