I've got an Asp Taclite, internal focus model. I just bought the only replacement bulb I could find for it, a "Triad 1" part # 3004. There are two other bulbs listed for this light, but that's where I get confused. The instructions that came with the bulb specify that the Triad II, and Triad III bulbs are for the external focus model. At least that's how I read it... Any help out there? TIA!