WHAT MAKES THE CHALLENGER DIFFERENT?
          First and foremost, the Challenger is an orbital floor machine.
Specifically, a random orbital floor machine. By this is meant that instead
of turning in one big circle at 175 RPM, the pad driver vigorously
oscillates, or vibrates rather than rotates. The vibration comes from the
1725 RPMs of each tiny orbit, or ellipse, or oscillating movement. Standard
or fixed orbital movement becomes random orbital movement (meaning it scrubs
"every which way but loose") when rotary "freewheeling" accompanies the
orbital motion. The Challenger's freewheeling rotary movement is in the
range of 90 to 100 RPM, adding even greater agitation to the equation.