High contrast cartridge alignment protractor improves visibility and eliminates errors. Avoids overshoot distortion to maintain sound Link to turntable setup guide with instructions printed directly on the protractor. Suitable for S-arm and any 1/2 inch mount cartridge. Colour:As Shown Material:Acrylic , . Dimensions: Length 21cm/8.27inch, Width 5cm/1.9inch 1. Place the protractor on the turntable plate with the hole on the spindle. 2. Move the cartridge/tonearm until the stylus is exactly in the center of the bullseye. Check that the cartridge is square to the outer grid lines. - If not, loosen the cartridge mounting screws and gently twist the cartridge until it is square. 3. Move the cartridge/tonearm until the stylus is exactly in the center of the inner bullseye, twisting the protractor as needed. Check that the cartridge is square to the inner grid lines. - If not, change the overhang (move the cartridge inward or outward along the axis) until the cartridge is square. 4. Repeat steps 2 and 3 until the cartridge is square at both points. Tighten the mount and recheck as above. Remove the protractor. Relax and enjoy! Package Contents: 1 * Vinyl cartridge calibration ruler 1 * Magnification card 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.