This 3/4 inch hose bibb vacuum breaker permits the attachment of portable hoses to hose thread faucets and prevents the reverse flow of polluted water into the potable water supply due to backsiphonage. It consists of a brass body construction, stainless steel working parts and a rubber diaphragm and disc. It is furnished with exclusive non-removable feature and equipped to allow sill cock to be drained. This hose bibb is ideal for inside and outside, health hazard installations requiring non-continuous pressure such as service sinks, swimming pools, photo developing tanks, laundry tubs, wash racks, dairy barns, marinas, and general outside gardening uses.