This is a replacement shaft seal for the Tesla Model S Large Drive Unit and Sport Drive. Early drive units have seen some early failures in this seal which can cause coolant to leak into the back side of the motor. It is also recommended that this seal is replaced if any repair work is done to the drive unit, as this is seen as a single use seal and should be replaced if removing the rotor. This is a triple wipe, PTFE, with TC style seals.