This is admittedly a self-inflicted problem, as you can find a list of compatible devices, but the experience of interacting with a product ecosystem where you have to check cross compatibility of every device with every other is miserable.

This device is perfect for runners of any level

This device works with Samsung galaxy S4 once software was updated to Jelly

awesome little device, a bit pricey, but awesome.

Fantastic small device for treadmill running and when GPS signal is not available

This is just a great little device.

The little device does work

This is a pretty nice little device so far.

I thought the device was a dud on my first try

It has an internal accelerometer and an ANT+ wireless chip allowing it to transmit your foot strike data to various ANT+ compatible devices.

great device that help me a lot in measuring the distance in the gym trademile

Overall, a pretty neat little device.

It's a good device, but tape it to your shoe or something

This is a great device.

Great little device

Great device, it helps a lot by showing your real instant pace

My husband says that the device was easy to install and sync, and is very unobtrusive when running

It was a little harder synching the device then I thought and seems to replace the wireless capabilities of the heartmonitor (in the respective versions).