A tool to stretch your strings out before gigs? Sounds like it's redundant, right?
I'm here to tell you it's not. I was skeptical before I received mine (thanks to Duane and Jamie at Stretcha), but not only am I firmly convinced about it's superiority to traditional string "break in" methods, two of my band-mates were so impressed they went out and bought them! The thick plastic is rugged and will survive being carried around loose in your gig briefcase (I know this from experience.) The process is simple (slip it under/over the string and slide), and quick - I was able to do three guitars' worth of stretching in about three minutes, and the strings behaved as well as my usual stretching techniques at the gig.
It's a simple, well made (so it'll last), tool that does exactly what it says it does. Hard to argue with, and I recommend it highly.