The A3L4AA-6L6G is an A3 series pilot light from Allen-Bradley, a 240V transformer-type unit with a green LED indicator. It's a panel-mount component for status indication on control cabinets and machinery.
What the Description Tells You
The description "A3 LIGHT 240V XFMR GRN LED" indicates a 240V AC primary transformer inside the housing, stepping down to power the green LED. This is a common configuration for panel indicators where the control voltage is 240V line-to-neutral or line-to-line, and the transformer isolates the LED from the supply.