New member in the Magicshine Seemee series bike tail lights. The Seemee 100 is a powerful rear safety light for road, urban and mountain bikers, with wide visibility, brake sensor and low power mode 100 lumens max, 72 lumens consistent, 260 degrees wide visibility, visible from more than 1.5 miles away Brake Sensor: 100 lumen brake light that lasts 3 seconds(heavy on battery usage, press and hold power switch for 5 seconds to turn this feature on/off) Ambient Light Sensor: Auto adjusts light mode and output depending on ambient conditions(only in smart mode) Low power mode: Power saving flash mode triggered at 5% battery and lasts 20 min Memory function: Saves the last mode used when the the light was turned off 3 brightness modes and 4 flash modes(double press to change modes, single press to cycle options) 1.5 Ð 12 hours runtime depending on mode 36 g in weight USB rechargeable(battery non-replaceable) Seat post mount and saddle rail mount IPX6 Waterproof