See all products of Dual Check with atmospheric vent (DuC-AV) FlowShield™ DuC-AV, Dual check backflow preventer with atmospheric vent FlowShield™ DuC, Dual check backflow preventer (sweat) FlowShield™ DuC, Dual check backflow preventer (MNPT) FlowShield™ DuC, Dual check backflow preventer (press) FlowShield™ DuC, Dual check backflow preventer (FNPT)