The A3L4AA-6L5G is an A3 series 120V transformer-type green LED pilot light from Allen-Bradley. It provides a green illuminated indication on a panel face, powered through an integral 120V transformer — a common fit for control stations and operator interfaces where a compact, panel-mount indicator is needed.
The description — A3 LIGHT 120V XFMR GRN LED — breaks down as follows: it is an A3-series pilot light, rated for 120V AC operation via an internal transformer, with a green LED light source. The transformer isolates the LED from the line voltage and steps it down to a suitable level, which is a standard approach for panel indicators in industrial control circuits. The green LED gives a clear visual status signal, typically for 'run', 'power on', or 'normal' conditions.