The supercharger isolator is part of the supercharger drive assembly and is located in the supercharger snout.  The original isolator as installed at the factory contains a spring mechanism and is notorious for noise and a short service life.  The spring in the original isolator wears a groove on the supercharger shaft, creating debris that will eventually cause the shaft seal to fail.  Our replacement coupler is precision-machined from a solid piece of high-grade thermoplastic and installs as a direct replacement for the original.  Our coupler is not susceptible to the issues that plague the original unit.
We highly recommend replacing the original isolator with this upgraded unit when an overdrive supercharger is installed on the car.