Just installed a d-tuna on my Charvel and figured I'd do a quick demo/review (apologies in advance for filming vertical...my wife was helping and I didn't want to make her do a second take!). Basically, if you have a Floyd Rose and want to change to drop D tunings, you know it can be tricky. This little device makes changing tunings on the fly pretty simple. Also, came up with a nifty way to stabilize the bridge by using some rubber bumbers to soften the impact of the sustain block against the body...way cheaper and easier to use than some other methods out there!