Mobile Fidelity's popular Geo-Disc tool takes the guess work out of mounting and aligning your phono cartridge allowing you to get the most out of turntable setup. The device is simple to use and extremely accurate, making proper cartridge alignment a snap (which is usually a tedious and time consuming process). Simply put the plastic disc on your platter and align using the printed graph based on the Baewald alignment curve. They even printed the instructions on the Geo-Disc itself so you don't have to worry about losing them. Realize the full potential of your sound system with a properly aligned cartridge.