That is the SON lighting system option, which is the SON front hub and the B+M front light and a Brompton-specific rear light. I bought a S6L in October this year with SON and moved its wheels to a 2006 S2L-X to make the S6L-X/BWR/SON shown. The SON light has a standlight feature which stays on for a few minutes via a capacitor so when stationary at lights it will stay on. I have it set on sensor mode so it comes on automatically when dark enough. It is however not as bright as good battery lights which I use to light up the road so I can see the road when night vision is ruined by oncoming SUV. If no cars existed, the dynohub light is ample. Its hard for me to show how bright lights are when moving, I only have handheld camera.