This eighteen inch wide track is most common among the larger Komatsu excavators including the PC-75 and PC-78 Series. This track comes with the Komatsu-specific guiding system with outside guide type rollers. This track also fits the Hyundai Robex 80CR-9, and the Sany SY-75C. The 450x83.5 is interchangeable with the 450x81 size so if you need help finding your exact fit please let us know.