DCI 4378 - Arm Mounted Automatic Control Unit for 3 HP, Surf, to fit A-dec® Cascade®Automatic Control Unit, 3HP, Surf, to fit A dec Cascade The Arm Mounted Automatic Control Unit features a new, simplified design with straightforward internals such as a single diaphragm control block without any moving pistons, springs, or O rings and a simple combination valve for water flow control. This unit is a direct replacement for A dec Cascade models. Quick install that takes less than an hour Replacement for A dec Cascade 12 ft. color