Raleigh RSP 1 watt silicone light, 100 lumens of highly narrow focussed beam, in my experience it's not very useful in the dark, but works adequately as a day light or this time of year when it's possible you'll be cycling in very dull overcast conditions or cycling home just before sunset.
For cycling in the dark I use either a USE exposure strada 900, or a Ravemen 1200 dual beam light.