90ISCS4025F - 2-1/2" Single Clapper Siamese Connection Bottom OutletDixon Valve 90ISCS4025F 2 1 2" Single Clapper Siamese Connection Bottom Outlet The Dixon 90ISCS4025F Single Clapper Siamese Connection is a durable fire department connection designed to supplement water supply to sprinkler and standpipe systems. Featuring a 90 degree bottom outlet configuration, this fitting allows efficient connection in tight or below grade installations while maintaining a clean, unobstructed waterway. The single swing clapper