4" x 2 1/2" x 2 1/2" Brass Fire Department Connection with Grooved Outlet Connection. FPPI Fire Department Connections are UL/ULc Listed and FM Approved in accordance with NFPA. Standard configuration is 4 NST Swivels. A limited number of regional threads are available for the swivels. Each FDC features solid brass construction and single clapper design.