The solar-powered Matrix PowerWatch 2, up close

A comparison of the original Matrix PowerWatch (left), which tracked steps and sleep, and the new PowerWatch 2 (right), which has a color screen, GPS and heart rate. Both are fully self-powered, no charging needed.

The reflective ring around the color display is a solar panel.

The watch is smaller this time around, but still has a Casio G-Shock vibe.

Besides tracking steps and calories and sleep, the watch now has GPS and heart rate, has a compass, and receives notifications.

The watch connects with Apple HealthKit and Google Fit, too.

If only more wearables were fully self-powered. Read our hands-on impressions for more details.