Mobile Fidelity Sound Lab GEO DISC - Mounting and aligning phono cartridges can be a tedious and time-consuming chore. Not with the Mobile Fidelity Sound Lab GEODISC! Finally available again after too long an absence, this cartridge alignment device is simple to use and extremely accurate. Just fit the disc on your platter and align using the simple printed graph based on the Baerwald alignment curve. You will never realize the full potential of your cartridge without the proper set-up tool. Click photo to enlarge. Great Set-Up Tool.