Fin is a tiny hardware product that you can wear on the thumb of your hand as a ring and it will make your whole palm as a Gesture interface.
For instance, a person driving a car can use Fin as their key, or take phone calls or control the music player without taking their hands off the steering wheel; a smartphone user can rub their index finger against the thumb to zoom their screens in and out and they can assign numbers to different sections of their fingers, turn their hand into a numeric keypad and tap in a phone number without even touching the phone.