The thick frame houses a variety of sensors that can measure movement and elevation. This includes an accelerometer, gyroscope, barometer, and humidity and proximity sensors. There's also Bluetooth and ANT+ for pairing a heart rate strap, footpod, cycling power meter and speed or cadence sensors.
The glasses use Intel's Real Speech technology, which allows you to ask and respond to questions in a natural way. You can ask a question, such as, "How's my pace?" and then follow it up with, "Is that good?" Think of it as Amazon's Alexa, but on steroids.