Buztronics Safety Strobes Presta/Schrader Valve Stem Lights, Red

The batteries lasted less then 10 hours. New batteries lasted less then 20.

Commuting in San Fran daily is heart pumping in itself when everyone is on there phones, not obeying traffic signs, lights, or laws. Having lights in the front and back of a bike is great but when your cruising by an alley, side street, or any street for that matter being seen from the side has been great. I think I have gotten away with two close calls due to these lights.I carry spare batteries in my backpack(going on 2 weeks same batteries they shipped with). They turn on from the vibration of the road and will shut off on there own when not moving. Can be seen during daylight. Super easy to install (fit both stem types) and they don't add but maybe a few grams if your a counter. A must have safety light. I will be buying more sets for my kids. They are kinda cool too.

The good: Vibration/motion sensors activate the flashing red LED for a reliable function. Improves visibility from the side.The bad: These will function during the day or night, wasting some of your battery (they take button cells). Had they also put in a light sensor to keep them off during the day, I'd give them 5 stars. Still, I use these on my bikes and they are reliable.The ugly:Overall: A simple and affordable method of improving safety and visibility from the side on a bicycle.Michael

Too bad there is no way to turn these off. The presta valve adapter works fine. The lights are fairly bright, and the batteries have lasted a long time so far. Visibility from the side is definitely increased, but don't expect people to see them from behind.

These give vital protection against getting side-swiped, say by a car entering a roadway from a driveway and merging into you. They do this by providing side visibility.It's true that the batteries on these don't last too long. However, replacement batteries are cheap and easy. I use LR1130 batteries, which supply 1.5v.I also use lightweight metal presta valve adapters with these, instead of the plastic ones that these come with, since the plastic ones cross-thread and thus become ruined easily.I would really like to see a metal-thread presta valve version of these. Those of us who are "serious" bicycle commuters would really appreciate it. Then we could skip the adapters.

These worked fine for the first bike ride but then one of them wouldn't shut off. We had to take it apart to make it stop blinking. These would be better if they had an on/off switch.

These lights won't last. The packaging they arrived in was destroyed. One of the lights was on and the other was dead. These lights are cheap novelty things that aren't worth the trouble.

Clever idea, fits both Presta and Schrader, but both units failed ON and could not be repaired. It has a clever little motion-sensing gizmo inside which works well, but something on the tiny solid-state circuit board failed closed (on) so one the light starts, it would not turn off. Disappointed.