This is the smallest bike light I have found (the face slightly bigger than a US quarter), and one of the brightest, despite having just 1 bulb. The rechargeable USB function is worth the money alone for what you save in batteries, and makes the light last for around 1 week or more (used every night). Unlike other Knog lights which constantly go off in your bag or pocket due to their super sensitive on/off buttons, with this model you simply hold the button down for a second to turn it on or off (click it quickly to change light flashing modes), so it rarely goes off in my bag--hence preserving the life of its USB charge. The small size is brilliant, especially for people who don't enjoy having to carry bulging bike gear around in their purse or pocket when their bike is locked up! Some of the parts, like the USB stick and plastic clasp, are a little flimsy, but I am careful and if it breaks I would definitely purchase another.