Features: Made up of acrylic acid material, durable, firm and non-slip for us to use. Light and precise, it can bring a good and wonderful calibration effect. High contrast cartridge alignment protractor provides improved visibility and eliminates tracking errors. Avoids the over-shoot distortion to keep highly quality sound Link to turntable setup guide with instructions included, printed directly on the protractor. Works with an S -Shaped arm and most 1/2" mounted cartridge. Specifications: Acrylic acid Size: Approx. 190x40mm/7.48x1.57inch Note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x