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.