Intonation Tool ACCU-LOCATOR/Intonation Adjuster for 1. FINALLY A TOOL THAT WORKS - machined from Zinc alloy. 2. WORKS ON MULTIPLE STYLES OF TREMS - original FR, FR special & FR 3. NO MORE HOURS OF DETUNING - make intonation adjustments under string tension 4. INCLUDES M2.5 HEX KEY - you 't have to find your "other" hex key to loosen the saddle screws, we include one with every tool 5. DOES NOT WORK ON - Kahler bridges, bridges, bridges with fine tuners that are at a 45 degree angle to the guitar top DIRECTIONS FOR USE 1. Block your so it can't move (you can use Guitars gauged Wedge Blocks). 2. Adjust your fine tuners to mid way to allow clearance for the toe of the tool 3. Tune the guitar to pitch using your favorite tuner 4. Clamp the tool with the silver tang just behind block and the toe of the tool wrapped under the fine tuner plate (see picture). Snug it up. 5. Loosen the saddle screw for you're working on. 6. your string is in tune, then fret at the 12th fret. If the note is , tighten the Intonation Tool's screw, retune and check again. If the note at the 12th fret is flat, loosen the Intonation Tool's screw to allow the saddle to move forward. Retune and check again. Do this for all strings until each string plays in tune open and at the 12th fret. Color: As Shown Material: Zinc alloy Package Contents: 1 x Guitar bridge tuning tool 1 x wrench Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.