FINALLY A TOOL THAT WORKS - machined from zinc alloy WORKS ON MULTIPLE STYLES OF TREMS - FR, FR special & FR NO MORE HOURS OF DETUNING - make intonation adjustments under string tension INCLUDES M2.5 HEX KEY - you don't have to find your other hex key to loosen the saddle screws; one is included with every tool DOES NOT WORK ON - Kahler bridges or bridges with fine tuners at a 45-degree angle to the guitar top DIRECTIONS FOR USE 1 - Block your bridge so it can't move. 2 - Adjust your fine tuners to midway 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 the block and the toe of the tool wrapped under the fine tuner plate. Snug it up. 5 - Loosen the saddle screw for the string you're working on. 6 - If your string is in tune, fret at the 12th fret. If the note is sharp, 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. Repeat for all strings until each string plays in tune open and at the 12th fret. Color: Photo Color Material: Zinc Alloy Package Contents: 1 x Intonation Tool Only the above package content is included; other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to vary slightly from the real thing. Measurement may vary by +/- 1-3 cm.