a swingable tremolo for a string instrument . a tremolo block connected with the tremolo body is in turn connected through a link with a sliding block on the bottom of the instrument . a first spring urges the sliding block against the tensile force of the strings . a movable stopper is engageable by the sliding block as it moves rearward . a second spring also urges the movable stopper forward . the tensile force of the instrument strings is greater than the opposite force of first spring but less than the sum of the spring forces of the first and second springs , whereby the tremolo body may be tilted up or forwardly to reduce string tension or tilted down or rearwardly to increase string tension , and upon release of the tremolo body , the forces of the springs acting on the sliding block and the movable stopper act against the tensile force of the strings to bring the tremolo body into an equilibrium state .