Made from extra long pile microfibers, the 9"x7" allows for proper pressure for safe and effective washing. There is also an opening at one end so that the inner foam can be removed for laundering, and so that the pad thickness can be changed by adding and reducing sheets of foam. Use the pad with no foam for a thin and flexible pad or add up to 3 sheets to make a thick wash sponge to hold maximum suds. The shorter, more dense, white fibers expand and hold the suds while the longer fibers gently tickle and agitate dirt and grit on the car surface. Happy washing!