1/2 in. x 3/4 in. x 6 in. MPT/SWT x MHT Brass Anti-Siphon Frost Free Sillcock Valve with Multi-Turn Operation. Prevents outside faucet freezing and protects against back siphoning. A built-in backflow preventer checks siphoning back into the water supply. The sill cock drains automatically upon water shut-off if the hose is removed or open. 1/2" Nominal copper sweat or 1/2" MIP. Import. Product is manufactured in china.