This is a handheld mobile mic for a vehicle adapter.
Motorola GMN6146D hand-held mobile microphone is a replacement part for use with a range of vehicular adaptors, which allow users to charge and operate two-way radios inside a vehicle.
Dimensions (inches)
3.50 H x 1.63 W x 2.25 L ( 88.90mm x 41.40mm x 57.15mm )