The Febco 856 is a double check detector assembly (DCDA). It was available in 2 1/2″-10″ sizes and was produced from 1993-2014. The body was made of epoxy coated ductile iron. The 856 utilized a 3/4″ 805YD for the bypass assembly. Two lead free versions are in production. The 856ST began production in 2011 and the LF856 began production in 2014. The 856 mainline body is visually identical to the 856ST and LF856 but the parts do not interchange.