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 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 portEasy to use: the silicone mount strap of the bike back light has 4 openings, easy 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 itWide 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 onUSB Rechargeable Bike Bicycle Cycling 4 Modes 5 LED Front Rear Light LampTechnical specifications:Brightness: 15 lumens Mounting Positioning: post bicycle seatBulb Type: LedSuitable Pipe Diameter: 12-32mmPlease long press for on / off.Colour:redMaterial:ABS+PCSize:7 x 2 x 1.7cmPackage Contents:2 * lights2 * straps2 * USB cablesNote:As the taillight is new, maybe have some low battery case. please charge before using. If this makes some problems , we feel really sorry.Only the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.