Improved model with better battery life Designed with a brake light function, which uses an accelerometer to determine movement, the Gravity illuminates using 100 lumens to let others know you are stopping 2 modes (runtime): Solid 20 lumens (12 hours), flash - 80 lumens (30 hours) USBC rechargeable li-polymer battery Includes brackets for seatpost and seatstay mounting and USB recharging cord Third party online retail sales prohibited