Littelfuse Model ALT-230-X Cross-Wired Alternating Duplex Pump Relay 195-240V 8-pin Plug-inLittelfuse ALT 230 X Description Alternating Duplex Pump Relay Product Model ALT 230 X alternating relays are used to alternate between two loads. An alternating pump relay 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. Littelfuse ALT