The Factory Cat 390 rider floor scrubber is the toughest Large sized rider auto-scrubber on the market today. The 390 is built with an extreme duty full steel chassis and an extra thick dual tank which makes the XR rider scrubber stand alone in its class of rider floor scrubbers. No other mid size rider auto-scrubber on the market today can compete with the 390 rider floor scrubber both in durability and value.