100 sq.in. of cleaning surface plus “heavy accumulation” scraper. Contoured V-shaped 1-1/1″ brushes clean sides, front, back, and soles. Soil directed downward. One foot secures unity while the other is cleaned. Structural foam blocks are held in place by steel swivel brackets bolted to all steel frame. Plastic bristles are “Soak-Proofed” acid and weather resistant. Ideal for indoor or outdoor use.