Review on Stay Safe While Cycling With G Keni Smart Bike Tail Light - Auto On/Off, Waterproof, USB Rechargeable, And Ultra Bright LED Warning Back Bicycle Flashlight! by Trendsetters Hare

The unit will go into a sleep mode when you stop. This is excellent for battery life at rest stops. I haven't been able to check the brake light function as I tend to ride alone but it does start up on moving after a stop. Small unit, made of good aluminum and has multiple flashing modes. Compact and several mounting options. Rear of seat bag, seat post, rear of carrier bags and even the rear of the carrier for me. Working well after well over 100 miles on the road. Feels like it will last a long time.