There a China knock off versions of the Lezyne on eBay, cheap. Sad to admit I have three of them, and they all work great. I assumed they would last a month of so, but they seem better made than my Cateyes - which are probably also made in China....

I have the genuine Lezyne USB for the front, two of them in fact, great flashers. Still flashing after all day rides, 100 charges and still fresh