cosmos. >> where did you come up with the idea? >> about five years ago on my couch. >> five years ago on your couch? yeah. >> this promises to keep guitars in tune forever. >> that first moment we did this, and turned the tuning, we're like wow. ♪ >> those kind of bends will take a guitar out of tune. don't have to worry about temperature, light, weather. it means you're not thinking about the tuning. you're thinking about playing, which is amazing. >> reporter: without nay any software or batteries the design is unique. >> it's very simple. this is all mechaniccle, based on a spring technology and constant tension. >> did you have any idea it was going to be received this well? >> yeah. i think most inventors actually think their inventions are going to be much better received than they actually are. it's been a five-year process,