The Woodford NIDEL® 37HD2-BR Backflow Preventer is designed to protect hose connections from backflow contamination in freezing and non-freezing areas. It has a brass and stainless steel construction which make it more dependable and long-lasting. This double-check backflow preventer from Woodford features a molded rubber diaphragm check valve. It has a 3/4" female hose thread inlet and a 3/4" male hose thread outlet nozzle. This Woodford 37HD2-BR Backflow Preventer has a non-removable bushing that is attached with Locktite®. It comes with a brass exterior finish. This backflow preventer also features a stainless steel stop collar and a stop screw which makes it theft-resistant. This device is ASSE 1011 approved. This Woodford 37HD2-BR Backflow Preventer is another quality product from Woodford that can give you years of trouble-free service. Woodford is today's premier manufacturer of wall faucets, yard hydrants, vacuum breakers and bath/lavatory drains and trim kits. All of Woodford's products is proudly made in the USA.