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 Nathan Hutchinson

I like the brake function to alert my MTB buddies see me hitting the brakes. But daytime visibility. the flashing LEDs are not that bright. (Compared to my 100 lumen Gygolite which you cannot look directly at without experiencing eye pain)I like the quality and strength of mounting to the seat rail (made of aluminum instead of plastic). BUT the light has to spin onto the thread of the seat rail mount and that takes a bit of time. But it's inexpensive and the accelerometer works fairly well when slowing down triggering the brake light.6 Month Update: I've decided that it just doesn't flash bright enough during the daytime to make car drivers aware. I will go back to using a 100+ lumen Cygolite