The Model 2621 dual set point voltage monitor is designed to monitor single phase equipment. The Normal LED indicates the relay is ENERGIZED. Toggle switch settings are as follows: Off lo – Relay de-energizes at Lo Trip – Relay energizes at Hi Trip On lo – Relay energizes at Lo Trip – Relay de-energizes at Hi Trip The Model 2621 is available in AC or DC versions. AC models of the 2621 are not frequency sensitive and can be used on systems from 50 to 400 Hz. Dual set points are ideal for battery charging applications.. Specifications: Contacts: SPDT; Mount: 8-Pin; VF Function: Pick Up/Drop Out; Voltage Range: 200-270VAC