This factory Mazda OEM replacement part is the upgraded design for 1994+ Mazda Miatas, but will fit all early Miata's as well. It is the rubber boot that installs on the base of the shifter, and is one of the first things to wear out and need replacement on your Miata. If you have a Mazda Miata and this part has not been changed already, it is most likely in need of replacement. This boot will also decrease shifting performance and feel as it keeps the shifter tight. When it tears from old age, it loosens up the shifter and increases the probability of missed shifts.