VEVOR Diamond Core Drilling Machine, 4in Handheld Wet Concrete Core Drill Rig, 1100-2400RPM Two Speed & 1-1/4" Thread & 2 Bubble Levels, 3-4in Drilling Diameter for Concrete Brick Block Stone, 1500WProduct Features 4 inch Wet Drilling Our lightweight handheld core drilling machine can perform wet drilling, and you can feel assured of accuracy when boring holes in a variety of surfaces with a 3. 1 4in 8 10. 2cm diameter hole capacity. More importantly, a industrial grade 4in core bit with 1 1 4" thread is thoughtfully included. Two Gear Speed Our 2 speed electric core drill, 950RPM 2100RPM, has a convenient gearbox allowing different speeds to