It seems that this Kickstarter project for the "World's first smart accessory for your watch" will not get enough funding. From the project description:
Glance is a smart accessory that tells you who is calling, helps you find your phone, enables motion control and activity tracking.
Glance is the first smart accessory to turn your existing watch into a smart watch.
Glance is designed to let you focus on the conversations that matter most, and live in the moment. Glance is precision crafted into a remarkably thin, light design with machined aluminium, fits on the wristband on your watch, and works well with your personal style.