3/8" O.D. (1/4" I.D.). Flexible stainless steel corrugated tubing with stainless fittings. A.G.A. approved for indoor or outdoor use according to ANSI Z21.24 and Z21.45. 1/2" Male I.P.S. x 1/2" Female I.P.S. fittings. 1 per bag.