EOS BIKE takes self-contained battery lighting to the next level. The self-contained unit feels virtually weightless on your helmet and makes the ultimate backup light for your 24-hour race. The EOS BIKE is light enough to throw into your jersey pocket for a late afternoon ride ensuring you'll have enough light to get home. It is drop proof and its use of high-grade materials ensures durability and strong resistance to water/weather/environmental conditions. Includes helmet, handle bar and headlamp attachments. The batteries 3 - AAA alkaline or lithium last up to 121 hours.