LAS VEGAS – The greatest, most game-changing product I saw earlier this month at the country’s largest health-tech event was a little black activity tracker perched on a small stand in a big booth.

This non-descript little tracker is the too-rare device developed in the true spirit of the healthcare system overhaul: that is, keeping healthy people healthy. It’s called Trio Motion, from UnitedHealthcare.

You can’t buy Trio Motion. The custom-designed device is free for employees at companies that UnitedHealthcare insures. Further, the companion wellness program, called Motion, is paying those employees for meeting daily activity goals. Up to $1,460 per person per year. Depending on the program, the funds might be designated to pay for healthcare. Or employees might just get a check.

Read why the little Trio Motion is such a groundbreaking device in my Fortune column HERE.