The Bigsby vibrato unit is installed on the top of the guitar and works in conjunction with a rocker bridge. The arm of the Bigsby is spring loaded and attached to a pivoting metal bar, around which the strings of the guitar are installed. In the neutral or unused position, the pressure of the spring counterbalances the pull of the strings, resulting in constant pitch when the strings are played. When the arm of the Bigsby is pushed down towards the top of the guitar, the bridge rocks forward causing the strings to loosen, lowering their pitch. When the arm is released, the strings return to normal pitch. The arm may also be lifted slightly to raise the pitch of the strings. The Bigsby is highly controllable within its range of motion and usually requires little force to operate. It is ideally suited to musicians who use slow, subtle, or extended bends. It has limited range compared to tremolo units using longer springs contained internally. Competing units, like the Floyd Rose and the Fender synchronized tremolo (or strat-style) are therefore preferred by some players.Manufacturing Method: CastManufacturing Material: AluminumApproximate Weight: 287 Grams/10.1 oz.Overall Length: 4 3/4”/120.65mmOverall Width: 3 3/4”/95.3mm*Designed for use on flat top electric guitars