Mercury H-21E 21" Hercules Floor Machine, 175 RPM, 1.5 HPMercury Hercules Super Heavy Duty 21 Inch Floor Machine. Precision Balanced, Heavy Duty 1. 5 HP, 66 Frame Motor For Easiest Operation Triple Planetary High Torque Transmission Handles The Toughest Jobs At 175 RPM 21 Inch Machine Size Scrub With A Brush 2 Inches Smaller Than The Machine Size, Or A Pad Holder With Riser That Is 1 Inch Smaller Than The Machine Size Pad Holders And Brushes Sold SEPARATELY. Pad Holder Sold Separately All Metal Chassis Adds