Blackburn Super Flea USB Rear Light. The Blackburn Super Flea USB delivers everything you expect from an exemplary rear light: it's incredibly bright, it's lightweight, it's easy to mount, and it's easy to use. The Super Flea USB is powered by a Li ion light that charges via an included USB cord. The rear light features two modes Flashing and Steady and runs for 28 and 15 hours respectively. At 36 grams, you won't even know it's on your bike while the LED fuel gaugecharge indicator lets you know exactly how much power you've got left.