floating tremolo is mounted on a roughly triangular chromed plate in the front of the guitar body, on the opposite side of the bridge to the pickups. The string tension is balanced against a single short helical spring, in compression rather than tension, mounted on the back of the "tremolo mounting plate". The spring is adjustable by turning a screw located towards the center of this plate. 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. The Fender floating tremolo also features a knob that enables the player to lock, and thus disable, the tremolo mechanism. This facilitates quick retuning in the event of a string breaking, and strives to provide tuning stability similar to a fixed bridge guitar. In practice, the lock doesn't generally achieve as much stability as a fixed bridge, leading some players to replace the mechanism with a fixed bridge and tailpiece. The "floating tremolo" was greatly favored by some surf music bands, particularly for its ability to produce a pronounced and distinctive vibrato on a sustained chord without disturbing the tuning of the guitar. To fully achieve this benefit however, correct setup, as per Fender's recommendations, was essential. An issue with the unit is the bridge itself, which Leo Fender over-engineered. The six individual bridge saddles were multi-grooved "barrels". The individual barrels were not grooved deeply enough to always securely hold strings during heavy picking. Each barrel had a tiny adjustment screw at each end. Adding the intonation adjustment screws, and the screws at each end of the bridge saddle to raise or lower the bridge as a whole, gave the bridge twenty separate adjustment possibilities . Many players found this too complicated . That, and the tendency of strings to jump out of the individual saddles led to a lukewarm reception for what was an excellent—if over-engineered—design. Later, many Jazzmaster and Jaguar players found that, with no retrofitting, they could replace the bridge