When it comes to the Sentry Aero Tail Light, the versatility is what we like most. First off, it's bright. 260 lumens is bright enough to be seen clearly in the daytime, and combined with the 260-degree visibility it's hard to be missed out on the road. Secondly, it mounts to both standard and aero seatposts, so it fits pretty much any bike from commuting rigs to high-end race bikes. The Sentry sports six different modes capable of running between 4. 5 and 30hrs, and it comes wrapped in an aerodynamic casing that looks sleek on your favorite steed..