Portland Design WorksGravity 80 USB Tail Light with Auto Brake Light(Return to Product Page)

Works well, very bright, good price

The light is sufficiently bright and accelerator works well. Top light lit up when you slow down or brake. But it lasts only around 3 hours, not enough for longer rides.

I think this light is a great idea and it works so it gets 5 stars - on a purely technical level it can still be improved. I would prefer to use the blinking mode on this light and then when you break it adds the solid light, however the blinking mode is an epileptic techno fit not a nice calm attention grabbing blink like some of the other PDW lights. So I don't use it, instead I have a second blinking light on my pack and I use the Gravity light in the always on mode that gets brighter when braking.

It's easy to use - it remembers what mode you were in - so when turning it on it always goes to the last mode it was in - very good UX design choice.

There are definitely times when it falsely decides i'm braking, usually when going over bumps - I'm actually happy with that since it is better than if missing detection of braking.

For brightness, I think it is the right amount. When lit up in braking mode it is very bright, I actually would not want it to be brighter.

Ive used this for a few months. No moisture or usability issues. The blink is sufficiently bright but not too obnoxious to follow. The lense helps disperse the pattern a bit to not blind other cyclists. Seems like it has to be charged about every 15 hours or so. I would buy one again.

The mount has changed from previous PDW tail lights. The old style isnt compatible which was a bummer.

The brake feature works OK. The light switches to a solid pattern pretty regularly on rough stretches of pavements (e.g. chip seal will set it off almost indefinitely). It does reliably detect harder braking.