The Plumber's Choice 5/8 in. OD x 1/2 in. ID x 6 ft. Gas Connector Stainless Steel for Gas Range, Furnace, Stove, 1/2 in. MIP x MIP Fittings GUHD-SS12-72A - The Home Depot
AMONIDA Stainless Steel Pipe Fitting, DIY Projects Threaded Pipe Fitting Elbow, G1in Female Thread Elbow for Gas Building Materials Hardware Plumbing - Amazon.com
Black Iron Pipe Gas Lines Installation - Sealing Fittings, Pressure Testing, and Bonding - YouTube