This boot seals the hole where the shifter comes through the transmission tunnel. It will almost always be ripped on cars older than 4-5 years, which will allow heat and noise to come up through shifter area. You will likely have to replace the small shifter boot at same time.
Unlike the Mazda part, this is made of thicker, more durable rubber. While it won’t last forever, it will last much longer than the stock part. Plus, it’s much less expensive than the Mazda part!
Mazda equivalent NA01-64-481B, fits all NA and NB models including the Mazdaspeed.