Check the listing for details. Regulator Flashback Arrestors Oxygen & Acetylene or LP, Propane B Size Fittings. Condition: New. Listed at 15.95 USD. Regulator Flashback Arrestors Oxygen & Acetylene or LP, Propane B Size Fittings Condition: New!Item Description:This is a "Buy it Now" listing for a Regulator Flashback Arrestors Oxygen & Acetylene or LP, Propane B Size Fittings. Fits Oxygen & Acetylene or LP, Propane Regulators with B-Size fittings, 9/16-18Fits between the regulators & twin welding hose.ISO 9001 CertifiedBlue is right hand thread for oxygen. Red is left hand thread for acetylene.Buy it Now Price: $15.95 Free ShippingPlease request a revised invoice through the ebay shopping cart if you need combined shipping.Please check out our other auctions. For more information on our company, check out our "about me" ebay page or google ATL Welding Supply.