See all products of BA type backflow prevention devices Controllable, reduced pressure zone backflow preventer, compact version. Controllable, reduced pressure zone backflow preventer, standard version. Controllable, reduced pressure zone backflow preventer, standard version. Controllable, reduced pressure zone backflow preventer, standard version. Bronze body. Controllable, reduced pressure zone backflow preventer. Bronze body. Flanged connections PN 16. Controllable, reduced pressure zone backflow preventer. Cast iron body, with epoxy coating.