This is our superb Platter Damping Ring (PDR), designed to fit tightly around the rim of the platter effectively forming a peripheral wave trap to absorb vibration / resonances / platter 'ring' and enhance rotational stability. This ring is 20m deep, so it fits most turntables with metal or alloy platters perfectly, but it will fit any turntable with a standard diameter platter, providing it is at least 20mm deep. (If you are using a deck with a shallower metal or glass platter, you should go for the 10mm deep model. We have sold over 1000 PDR's and the feedback has been amazing, with them working sonic magic on turntables as varied as Thorens, Roksan, Linn, Project, Ariston and Garrard. The PDR is made from a particular type and grade of rubber-like synthetic polymer, specifically selected for its damping properties at the frequencies which cause problems within LP replay systems.