quick Brake light question

Hey guys jus a quick question, my brake light aren't working but just wondered whether the the brake/normal light bulb should be a double filament or just a single filament. stupid question i know. cheers guys

Batman

My cars an tintop 83 gti

Yeah should be a double filament bulb (stop and tail)
Bobby

Yeah should be a double filament bulb (stop and tail)
Bobby