CygoLite 110 to 1000 lm Bicycle Headlights
About CygoLite - "Founded in 1991 by a group of Southern Californian cycling enthusiasts who envisioned bicycle lighting systems utilizing the latest technology with trend setting designs, Cygolite developed a line of systems that made it synonymous with innovation and quality. Over 20 years later, we still lead the way, creating rechargeable lighting systems inspired through test rides on the trails and roads then engineered and assembled in our California headquarters."
A lumen is a measure of the total "amount" of visible light emitted by a source. The higher the lumen rating, the brighter the light.