The 574 Series testable, reduced pressure-zone backflow preventer from Caleffi North America is used in residential and commercial plumbing systems where ASSE 1013-type devices are required by code. The 574 Series prevents accidental contamination of the distribution water supply system when there is a reduction in pressure in the supply system, like a main break or periodic flushing, or an increase in pressure in the building plumbing system, like a missing or nonfunctioning domestic hot-water expansion tank. 414-238-2360; www.caleffi.com.