Optimum Opti-Mitt provides a great wash medium for Optimum No Rinse or Optimum Car Wash. The 85-90 pores per square inch allows for the wash solution to flow to the surface and add great lubricity during the wash to protect all automotive surfaces from marring. Opti-Mitt is also very absorbent and can pull all the dirt and grime safely and effectively. The yellow backing of Opti-Mitt is much coarser and is designed to be used as a bug sponge or cleaning wheels. So in essence, you will get two wash mitts in one with Optimum Opti-Mitt.