This is a New Old Stock (NOS) British Prefocus (BPF) or P36 base yellow bulb (12V, 45W), made in England decades ago.
They are foglamp bulbs, which have horizontal filaments, but they will work fine in a spot or driving lamp as well. They are correct for Lucas 576, 700, or Ranger lamps.
We have only a very few of these bulbs left, and when they're gone, we cannot be sure of getting any more.