Hi Shouter, Locking tuners are machine heads with a hollow post. Inside this post is a smaller post which, when tightened, comes up through the larger outer post, and grabs the string as the string passes through. Picture a piston inside a cylinder. The advantage of this is that you don't need to wind the string around the post, the little inner "piston" is holding it securely for you and it can save some time when changing a string. The design originally came from a company named Sperzel, and was a standard feature on Fender's Plus series of Strats and Teles from the late 80s onward. The downside of locking tuners is that they add some weight to the headstock, and with the earlier Sperzels, the adjustment wheel which controlled the inner piston could come right off, and go to that place where the socks from the dryer go, invariably in the middle of a gig. There are newer versions of locking machine heads that alleviate the latter problem. In your particular case however, I might suggest a drop tuning machine head made by a company named Hipshot. A friend has one on his Tele, and just raves about it. If you only detune the low E string, that's what I'd recommend. The gizmo is large enough that you can only fit one of them on the average headstock. Hope that helps. Timothy