Cash Acme 17217-0000LF BF1 3/4-Inch Dual Check Backflow Preventer with Threaded Union Inlet, Lead Free Cast bronze body and brass union inlet connection The Cash Acme BF -1 is available in 3/4" and 1" sizes and incorporates a female threaded union inlet and a female threaded outlet The BF Series is certified to ASSE 1024 and CSA B64.6