Product Highlights Alternating loads allows for equal wear on both pumps lengthening their operation life The controlled relay alternates each time the control switch opens Two LED indicators show the load that is energized by the SPDT output relay The DPC-ACS model is a standard duplexing controller providing the automatic alternating sequence The DPC-ACL offers the same automatic sequencing as well as A-B or B-A sequence lock selectable by a three-position toggle switch