Portland Design Works' Gravity 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. To allow the accelerometer to calibrate, always install the Gravity on your bike before powering it on. Hold the power button down for 1 second to turn the light on or off. Then, keep your bike still for 1 second after pressing the power button to complete the calibration.
The Gravity Tail Light has a redesigned mount that works with the included seatpost and seatstay brackets.
- Automatic accelerometer brake light function shines 100 lumens bright
- 2 Modes (runtime): Solid - 20 lumens (12 hours), Flash - 80 lumens (30 hours)
- USB rechargeable li-polymer battery
- Weatherproof exterior for all season riding
- Includes brackets for seatpost and seatstay mounting
- Mounts vertically or horizontally
- Includes Micro USB recharging cord
- Weight: 1.9 oz