The Febco 856ST is a double check detector assembly (DCDA). It is available in 2 1/2″-10″ sizes and production began in 2011. The body is made of epoxy coated ductile iron. The 856ST utilizes a 3/4″ Watts LF719 for the bypass assembly. The 856ST mainline body is visually identical to the 856 and LF856 but the parts do not interchange.