Frost Proof Self-Draining Hose Bibb  Vacuum Breaker | Lead-Free, Solid Brass

Designed for use on yard hydrants and hose bibbs to prevent the reverse flow of polluted water into the potable water supply due to back siphonage. This self-draining Lead Free hose bibb vacuum breaker will automatically drain when the water is shut off, even when attached to a hose. Now you won't have to worry about leaving hoses connected during cold weather. These protect against potential health risks and contamination in potable water. Comes complete with a breaking set screw. Once tightened set screw will break off to prevent tampering and removal.