4 Modes bike back light: comes with 4 modes completed within 1 switch, including full brightness, half brightness, fast flashing and slow flashing, which can be seen from a far distance, and you can be easily noticed by others in the dark, increasing the visibility and safety USB rechargeable design: built in 330 mAh rechargeable lithium battery and a USB port design, you can use any device with a USB interface to recharge the bike tail light; And there is a USB cable attached to each bike tail light, allowing you to charge from your computer, power bank or any device with the USB port Easy to use: the silicone mount strap of the bike back light has 4 openings, easy for you to install on the handlebars and seat posts, and bike tail light tightly fits around most size handlebars and seat posts, you don't need other tool to install it Wide range of applications: not only can these rear bike lights provide illumination for most bikes, such as racing bikes, mountain bikes and so on, but also they are suitable for attaching to most bike frame, seat post, handlebars or helmet, hook onto your belt, running gear, reflective vest, backpack, dog collar, harness and so on USB Rechargeable Bike Bicycle Cycling 4 Modes 5 LED Front Rear Light Lamp<br><br>Technical specifications: Brightness: 15 lumens Mounting Positioning: post bicycle seat Bulb Type: Led Suitable Pipe Diameter: 12-32mm Please long press for on / off. Colour:red Material:ABS+PC Size:7 x 2 x 1.7cm<br><br>Package Contents: 2 * lights 2 * straps 2 * USB cables Note: As the taillight is , maybe have some low battery case. please charge before using. If this makes some problems for you, we feel really sorry.