Quick connect regulator-to-hose set with check valve. 200 PSI maximum pressure. QDB31 (fuel gas) and QDB32 (oxygen gas) components. Size-9/16 inch-18. Provide fast, reliable and positive connections and quick disconnections for torches, hoses and regulators. Brass construction provides long service life cycle tested over 10000 operations indicating a service life of 10 to 12 years of comparable use. Non-interchangeable oxygen and fuel gas connectors prevent accidental gas mixing.