This 3/4" hose connection vacuum breaker backflow preventer permits the attachment of portable hoses to hose thread faucets and prevents the reverse flow of polluted water from entering into the potable water supply due to backsiphonage. It consists of a brass body construction, stainless steel working parts, a rubber diaphragm and disc, a draining stem, and a break-away set screw for tamper resistant installations. It 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. Check with local inspection authorities for installation requirements. Maximum pressure is 125 PSI (8.6 bar).