ATL Welding Supply stock a large quantity of Twin Welding Hose for oxy-acetylene or oxy-propane cutting. We have a variety of lengths and diameters. All of our hose include the B-size fittings. B-size is 9/16-18 thread. We can get hose with the old A-size thread if needed, just call us to order. We stock Grade R & Grade T twin welding hose. Grade R is for oxy-acetylene. Grade T is for oxy-propane. We can also get single line hose on special order.