Prier 400 Series Residential frostproof anti-siphon wall hydrant provides a year round source of water in areas that are subject to freezing temperatures. The hydrant valve is connected to the supply piping in the heated portion of the structure, eliminating the possibility of freezing. The residential design includes an anti-siphon vacuum breaker with EPDM backflow preventer and backflow check valve, solid brass body, ergonomic half-turn easy-open handle design. Prier anti-siphon frostproof sillcocks assure protection against freezing and undesirable back-siphoning. Unlike anti-siphon attachments, which must be manually drained to prevent freezing, the integral anti-siphon design is self-draining. Built in angle (4 degree) for perfect drainage pitch.