I guarantee the D tuners, if for some reason they do not fit or work for you, or you just don’t prefer them, I have a 30 day money back guarantee on the tuners. They really do work, I am using them. They come on and off easy too. I don’t always need D-tuners and I can put these on and take them off as I feel like it. Then I can use my regular tuning pegs without having to work around the set screws that are on normal D-tuners while doing every day tuning, and at shows. I am really, really impressed with these.