Uniform baked-on polymer coating leaves no gaps to resist corrosion and chemicals and protect against leaks. Manufactured without soldered or brazed joints form type 304 stainless steel. Broader face nuts and fittings with smoother connector ends seal with less torque for easy installation. 3/8 ft ' ID (1/2 ft ' OD) with fittings. CSA IAS design certified for gas appliances indoor and outdoor.