Here is an instrument control panel with DELCO and a 'B' and 'M' on face.
Is this for an automobile, boat...airplane????
faceplate is about 8 x 2 inches. overall has a heavy feel. end of key looks like a small gear.
(have a similar smaller one with 'DELCO' named and 'HEAD AUX REAR IGN' each over one knob on face)
as always, answers are much appreciated.