The headlight from Boy Go Fast came quickly and this is what I received.... images below.
Headlight assembly with 2 conductor pvc insulated lead with an on/off slide switch about 2 inches from the assembly. The light housing was stiff blue plastic with a galvanized sheet metal formed bracket. The whole assembly and switch didn't look very weather tight. Is it a POS? Well, it was only $9.99 + $8.00 shipping. I will give it a trial.
The blue plastic housing looks to have a seam where the lens for the LED lamps are but I was unable to screw or wedge it off. I will try to work with it before dissecting it.
The additional hardware consisted of a mounting bracket for .75 or 1.0 inch tubing, a rubber gasket inside the bracket (assumed for preventing the bracket from rotating), a pointed set screw , a washer, a lock washer and two nuts which were of a size to thread on the set screw. The light was packaged with hardware in the plastic bag which scratched the lens in shipment.
There were no installation instructions or manual included.
There must be a rectifying circuit somewhere. I opened the slide switch but there is no circuit in there. All stuff must be in the light assembly with the LED's.
I have a 6 volt DC source to try. Since it would be 6 Volt AC from the MB engine, It should work connected in one orientation and just as I suspected it did when DC was applied from the appropriate configuration.
The light was substantially bright. Inside the house, in day time, it did have a blinding light from the 9 LED's when pointed at my eyes from 2 feet away!
Overall it is minimalistic.. The switch does not seem to be weather proof, nor the headlight assembly. The housing of the lamps seems to be a brittle plastic.
I will be installing it tomorrow and get a better idea of how it works on board. I will test it in the evening to see how it compares to my 3 watt 6 volt bicycle lamp.