Clear and accurate calibration allows you to easily read data. Helps eliminate tracking errors, especially on the inner grooves of the record. Ensures proper alignment for optimal sound. Works with any standard 1/2 inch mounted cartridge. Usage: 1. Place the adjustment ruler on the turntable shaft of the record player. (Points are red) 2. Move the gauge and the arm to drop the stylus at point A. Adjust the angle of the cartridge so that the leading edge and the horizontal line on the scale are aligned, which is more conducive to mirror reflection. 3. Move the gauge and the arm to drop the stylus at point B. Check that the leading edge of the cartridge is square with the grid lines on the scale. 4. Repeat steps 2 & 3 until a square is formed at both points. Simply loosen the screw to adjust the cartridge position, and after alignment, tighten the fixing screw. Color: Transparent Material: Acrylic Package Contents: 1 x Adjustment Ruler 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 be slightly different from the real thing. The measurement allowed error is +/- 1-3 cm.