Hipshot Tremsetter 401000 Tremolo Stabilizer Eliminates tremolo flutter and sag Completely invisible once installed The Hipshot Tremsetter greatly improves guitar performance by stabilizing your tremolo It automatically returns your full-floating tremolo to its exact "zero" neutral position, eliminating flutter and sag, so your guitar remains in tune With the Tremsetter you can bend strings, play bridge harmonics, aggressive rhythm parts or mute strings, and the bridge remains stable Best of all, the Tremsetter is total retro-fit