I've only been able to find a little bit about these lamps. I have a Radios No. 18 head lamp. Its reflector is slightly splotchy and tarnished and there is a little dent at the point. They are a pretty and classic example of the streamlined bullet style of the era with a little Art Deco flare on the spring loaded lens release. A recent auction on Ebay France turned up a couple of really nice specimens. Unfortunately, somebody else wanted them more badly than I did. Photos are from the seller.
They seem to be going up in price with some NOS examples going for over $100. Someday I'd like to get a nicer No. 18 like the one pictured here, with what looks like a spotless and well-preserved reflector. The fender-mounted tail lamp is also very beautiful: