Using a multi LED array, the Sabre 50 Tail Bike Light from NiteRider is visible and eye-catching both day and night. Featuring super-bright LED's and projecting a powerful and ultra-bright 50 lumens, it's a lightweight portable package that's head-and-shoulders above other self-contained LED tail lights on the market. With an aerodynamic design, it sits directly behind the seat post and produces less turbulence. It has built-in amber side lights for 180-degrees of visibility and it's USB rechargeable with up to 7.5-hours of run time when fully charged. Always brilliant when the sun goes down, the NiteRider Sabre 50 Tail Light makes your ride safer after hours.Daylight Visible Flash (DVF) 50 lumen super bright tail light Easy on and off seat post strap mount with quick release tab Amber side lights for 180 degrees of visibility Convenient USB rechargeable Be seen by cars = Be Safe Built-in universal clip FL1 Standard IP64, water resistant Lumen Output: 50 Run Time : 1:30 ? 7:30 hrs Charge Time: 1:30 hrs Weight: 28g Battery: Li-Po LED Tail Light Seatpost Mount USB Cable Made in the USA for more than 25 years!