The Freezeless Woodford Model 19 outdoor wall faucet is designed and intended for year-round residential irrigation purposes regardless of outside conditions. A patented pressure relief valve (PRV) prevents bursting during freezing conditions, even if a hose is inadvertently left connected to the faucet. The faucet will still freeze, however it will not rupture. As a result, this product prevents water damage when hose is left on. Patents and patents pending see woodfordmfg.com/patents 

What is a Pressure Relief Valve (PRV)?
The Woodford Model 19 has a Patented resetting pressure relief valve (PRV) that prevents the faucet tube from rupturing, and consequent water damage during freezing conditions, even if a hose is inadvertently left connected to the faucet. The Model 19 will still freeze if hose is left connected to the faucet, however , it will not rupture.

Hole in the wall? Purchase an RK-OSF Over-Sized Flange Whether updating an old faucet with a new Woodford freezeless faucet or improving an existing installation, the new RK-OSF Over Sized Flange can cover a larger hole due to previous installation plus secure the faucet to a solid surface. The RK-OSF can be attached to any new or existing Woodford Model 14, 16, 17, 19 and 101 wall flange. Outer holes are spaced a full 3 1/2-in apart for better mounting screw contact in masonry or siding.