USB-rechargeable bike lights have to be one of the most useful innovations of recent years. No more fiddling around looking for spare batteries, easy to top up and charge anywhere - whether from your computer or a USB powerbank - they take a lot of the hassle out of ensuring you have lights ready when needed.
They also make for great daytime running lights - there's an increasing realisation that "blinky" front and rear lights have an important part to play in visibility during the day, not just at night.
What's better than a compact, rechargeable front or rear light? How about a light that can fill either role. The Stix Switch can be used as either a white front or red rear light depending on what you need.