These caps are located on the ABS sensor holes on the rear axle housings of 96-02 4runners and 96-04 Tacomas that have ABS style rear axles, but No ABS on the truck. Also needed if running aftermarket chromoly rear axle shafts in an ABS style axle housing. DOES NOT FIT ABS HOLE IN DIFFERENTIAL / THIRD MEMBER. This is a genuine Toyota part. Sold individually.