Reverse flow check valve. Fuel gas. LH B-size male to B-size female nut. 50 PSIG (345 kPa) pressure. Mounts easily on torch, is readily seen and can be removed for periodic testing. Flows cut up to 12 inch steel plate or handle heating tips (1200 SCFH at 50 PSIG). Stops reverse flow at point of origin. For torch and regulator applications. Guard against danger caused by plugged tips, over-pressurizing or incorrect start-up procedures. Proper check valve installation helps prevent accidents caused by gases mixing in hoses, regulators or cylinders. Machined high quality brass with stainless steel operating spring and valve disc. Low open/close pressures, 3 oz open valve and 10 oz reverse pressure to positively close valve. Viton check valve seat material.