The Gravity+ Tail Light has redesigned mount that works with the included seatpost and seatstay brackets. If you'd like a backpack clip compatible mount, you can find one here. 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. DETAILS 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
