Series LFN9-CD is designed to prevent high hazard backsiphonage backflow and low-head backpressure (10ft. or less) from contaminating the potable water supply. The LFN9-CD is ideally suited to prevent backflow associated with hose connections and may be screwed directly to the sill cock, yard hydrant or wall hydrant. Typical installations include service sinks, chemical dispensers, sill cocks and frost proof hydrants. WATTS® Backflow Preventer, Series: LFN9, 3/4 in Nominal, Female Hose Threaded x Male Hose Threaded, 125 psi, 180 deg F, Brass Body, Import