I have bought many other lights for my ebike at the same price, but this one is the best! Very good build quality, charges with USB, the battery lasts a long time, and most importantly: it has the brightest light out of all the others I have tried, with 3 modes - strong steady light, weak steady light, and blinking. As for how waterproof it is, I don't have an opinion since I don't take my ebike out in the rain, but it seems sturdy and indeed water-resistant. If you are looking for a reliable light for your bicycle at this price, go for it without hesitation!