This is a really cool thing for the guitar. We've carried them in our store for about two years now, I have them on all my guitars.
I won't play without it any more. You can put it on and remove it in just a few seconds. Goes on and off like a post-it note.
Here's a few seconds of a video on how that works: https://www.youtube.com/watch?v=NDX1aLI ... be&t=4m52s
More info at http://softnek.com/
Here's me playing with one: