Littelfuse Model ALT-115-X-SW Cross-Wired Alternating Duplex Pump Relay with Switch 95-125V 8-pin Plug-inLittelfuse ALT 115 X SW Alternating Duplex Pump Relay Product Description Model ALT alternating relays are used to alternate between two loads. The ALT is commonly used in duplex pumping applications to balance the runtime of both pumps. The Model ALT X has an internal cross connected relay and is used in applications where two high level floats are used. These floats are commonly referred to as lead and lag floats. The Model ALT X SW adds a built in