With a whopping 100 lumens and smart sensor technology, the Light & Motion Vya Pro Tail Light represents the next evolution of cycling safety in an ultra-compact, convenient design. Smart sensor technology senses motion and automatically turns the Vya Pro on when inserted into the included, easy-to-use seat post mount, and then turns off when your bike is parked or if you remove it from its mount. A powerful 100-lumen output optimizes your visibility on daytime and nightime commutes alike thanks to the variable SafePulse beam pattern, while innovative amber side lighting enhances critical visibility when pedaling through crowded intersections. Plus, the Vya is made from a bio-renewable material that's not only impact-resistant, but is also waterproof to 1 meter for reliable use under changing weather conditions.