ADVANCED DESIGN - State of the art patented design, LED configuration with 2 rows of 5 LEDs. Easy-to-access power button for quick on/off/mode selection. Swiveling base pivots between horizontal and vertical positions to suit your bike's geometry. USB RECHARGEABLE - This Bike Tail Light has a built in 600 mAh rechargeable lithium ion battery, which emits brightness of up to 120 lumens so that it can alert other pedestrians and motor vehicles at night, and it comes with a CHARGING CABLE that charges from your computer, power bank or any device with a USB port. WEATHER RESISTANT - Solid construction ensures it performs well in wet conditions and keeps out dust and dirt. IP64 waterproof performance can withstand most rainy and snowy days, so feel free to ride your bike anywhere regardless of climatic condition. 7 LIGHT MODE OPTIONS - The Tail Light features a one-touch button with 7 different lighting modes depending on your preference, including high, medium, blink, pulse, SOS, left/right flash and left/right pulse. EASY INSTALLATION - Just place on seat post and secure silicone rubber strap for a quick, snug fit. Stretchable strap is suitable for any size of seat post. These bike taillights greatly improve your safety while on the road or trail.