I used a light fixture from Lowes that use a MR-11 12 volt 10-watt halogen bulb. This is the same bulb used in those $100 plus bike light systems! Look around in the track lighting section. This is a small weighted base spot light with built in 12-volt supply for the MR-11 bulb for $14.99. Remove the base and retain the bracket and light fixture. Use an EMT clamshell type EMT conduit clamp for mounting the bracket and the fixture to your handlebar. The MR-11 bulbs are sealed with an integrated lens so it's weather proof. A 12 volt 4 to 5 amp-hour sealed lead acid battery will run the light for several hours and you have plenty of light.