Steel Dragon Tools 8&rdquo; 185 Wet Dry Core Drill Rig and Stand for Diamond Concrete Drilling Boring Wet Core Drill Rig Drills up to 8" Holes through Granite, Stone, Marble, Concrete, Asphalt, Powerful 3500-watt Motor delivers Extra Torque for the Toughest Drilling Jobs Bottom Base measures 8" x 7" with 4 Bolts amd brackets 2" x 2" Column with Rack and Pinion Gear System for Exact Drilling Depth Diamond Wet Core Drill Bits are available from 1-1/2" - 14"