Cleverly engineered to warn other road users when you're slowing down, this rear light is equipped with an accelerometer. This special technology boosts its brightness to 100 lumens as your speed decreases. This makes it a perfect brake light for alerting traffic behind you in the exact same way as a car's brake light does. Coming complete with a silicone strap, this handy rear light easily mounts to your seatpost without the need for any tools. Glows brighter when you slow down The Lumasense uses an accelerometer to boost brightness to 100 lumens as your speed slows, alerting the traffic behind you. A silicone strap mounts the Lumasense V2 quickly and easily to your bike – without the need for tools. Brake with confidence Let traffic know you're slowing down with the Lumasense's clever accelerometer that increases brightness as your speed reduces. Tool-free mounting Quickly and easily mount your light wherever you need it - on your bike or helmet - without the need for tools.