The QIL range of rail mounted indication lights are 13 mm in width and complies to IEC 60947-5-1 requirements. The red LED indication on the single pole device can be used in any distribution board to indicate the presence of electrical voltage in the circuit. The double pole unit can be used to indicate the state of primary and secondary power supplies through a red and green indication. This is particularly useful for backup power generation when used in conjunction with a changeover switch.