Portland Design Works Gravity Plus USB Tail Light
Portland Design Works Gravity Plus USB Tail Light, The Gravity Plus USB Tail Light has a built-in accelerometer that detects deceleration or swerving and automatically changes to a super bright solid beam to warn following traffic. There are two modes solid and flash both of which transition to the 100 lumen solid beam upon braking or maneuvering your bike. You must calibrate the light each ride but it's as simple as powering it on and keeping your bike still for one second to allow calibration. The Gravity Plus tail light includes brackets for mounting on your seatpost or seatstay and can be positioned horizontally or vertically depending on your preference.