Wet Drill Core Bits for Hard Concrete, Granite, Brick, and Block - 3.25" Diameter 1-1/4"-7 Threaded #30/40 Diamond Grits #30/40 diamond grit, designed for drilling hard concrete, masonry, hard brick, granite, and other hard materials Diameter: 3-1/4 inches Thread: 1-1/4"-7 threaded Drilling depth: 14" Drilling method: WET only