idem FCC Certified, Rechargeable Smart Bike Taillight That Turns On and Off Automatically, Deceleration Signal When Bike Slows Down Abruptly, SOS Distress Light, and Optional Theft-Deterrent Alarm.

This is the best product for the money! Quality is perfect, the tail light can be fixed on a seat post or on a saddle - both brackets are supplied. Very bright and deceleration sensor works ideally and turns on the brake light mode just in time! I purchased 4 or 5 various tail lights including with deceleration sensor and none of them worked properly. Had to returned all of them. But this light does its job just perfectly. Price is very reasonable!

The brake light feature just simply doesn’t work. Randomly turns on while braking making it useless as a safety feature. The light died after first exposure to rain which means it lasted about a week for me.

This is one hell of a great light. It is extremely bright and all the features work great--like the braking feature, SOS 'fallen and I can't get up' feature, However there are two features which I don't like.1. The alarm works perfectly, but it will raise the dead! When you turn the light on/off, the alarm beeps once--enough to startle everyone on the train when commuting. That one beep wakes everyone up.On several occasions the alarm went off accidently and I couldn't stop it. It happened once at a Home Depot in Manhattan and all the security guards had to come over. I literally had to take my jacket off to muffle it while I ran out of the store. On another occasion it went off at a bike shop and deafened the poor mechanic and everyone in the shop. They told me that they had to take it out in the back yard until the battery ran out.So far I have purchased about ten of these lights because they are so good and so efficient but I open them up and cut the wire to the buzzer.If you purchase this light make sure and use the tethered rubber cap to keep water out of the micro-USB charging port or else water will quickly damage the port.

I got this mostly for the automatic brake feature. Unfortunately, it doesn't work as well as I expected. It only activates when I brake abruptly or accelerate rapidly. It doesn't light up at all when I'm coming to a stop from any speed unless I slam the brakes hard. I thought maybe the angle of the light was an issue, but even when the light was parallel to the ground, it wouldn't activate when slowing down.Also, when mounted under the seat, the charge port is blocked by the seat rail. This means you have to remove a security screw before unclipping it for charging. I suppose it wouldn't be a problem if you didn't use the little tapered security screw that holds the light to the mount, but then anyone could just easily unclip the light and smash it to disable the alarm.I wouldn't recommend this product if you intend to mount it as pictured (under the seat) or want a reliable braking feature. I'm pretty sure the first time I charge this thing, it'll probably not be worth the effort putting it back on the bike.Advice for the manufacturer:Relocate the charge port where it's accessible in any mounting positionBe able to adjust the sensitivity of the automatic braking featureChange the terms for "night mode" and "all day mode" (it doesn't make sense that the light doesn't flash all the time in night mode and does in day mode)

This is a great multitask smart taillight. I mainly use it for the taillight only, but it’s also good for protecting my bike from thieves. Also, the quick start guide was incredibly easy for me to install. I loved the design very creative and smart. The packaging is very neat and colorful, I very much appreciated that. Very bright and effective bright lights. I like the ability to choose the solid light, slow flash, or fast flash. Great for daytime too, so drivers are aware of you – catches their attention. The fact that it is waterproof is a plus

This is exactly what I was looking for. Great product that makes me feel safer riding in the streets of my city. My favorite features are that it lights up brightly if I break abruptly to warn riders or drivers behind me and that it automatically switches off the taillight during the day to save battery power. I would definitely recommend this to someone looking for a taillight that works right out of the box and is easy to install!

Supposed to come with a saddle bracket. DID NOT., could not use for the application I wanted to.

Good product and design for what it is intended to do.Not visible in daylight. For that you need something like the Cygolite Hotshot– 100.Since it is designed to be an alarm system, it has to stay on the bike, and thus is permanently attached to it: it may attract a thief, and also it makes it hard to recharge, since you have to do it while installed on the bike.