The Bontrager Ion 100 R Front Light is ideal for cities & towns, to make you safe & seen. The 100 lumen output, is produced through the a wide angled, focused optics lens, which is visible from upto 500m away in day time. If you are commuting during the daytime, 100 lumens are all you need to be seen by cars & other road users. The light also features an auto-brightness light sensor, so it will save you power where needed.