The ferrule ends of the strings are held on the top of the guitar in a tailpiece plate called the "knife plate", which emerges from the mechanism, rather than the strings vanishing into the mechanism as with the synchronized tremolo. It is the knife plate that is moved when the tremolo arm is operated. Unlike the synchronized tremolo, the bridge is not moved directly by the mechanism, but only by the movement of the strings, and is allowed to tilt to accommodate this movement. This is called a "floating bridge".