Review on Cygolite Hypershot 350 Lumen Bike Tail Light with 7 Night and Daytime Modes, User Adjustable Flash Speeds, Compact and Durable Design, IP64 Water Resistance, Secured Hard Mount, USB Rechargeable, Ideal for Busy Streets by Michael Briggs

I have replaced my single Cygolite bulb with a 350 lumen Cygolite which has worked flawlessly for years. This item is absolutely BEAUTIFUL! It is incredibly bright and easy to see in full sun. Battery life is understandably shorter than lamps that aren't as bright, but you can adjust the light to extend battery life if desired (see attached chart for flash rates versus battery life). I just can't say enough good things about this flashlight and all the Cygolite products I've used to date. Outstanding quality and unmatched reliability. I haven't had any water issues and have been exposed to heavy rain for several hours, but I would recommend removing the light before washing the bike. The key word is "sustainable”, not "waterproof”.