MK Diamond 158663 1-1/2-Inch Dry Premium Grade Core Bits For Masonry Dry premium core bits are design to tackle soft brick and concrete block drilling operations Laser-welded technology and inventive bar-slot cooling to promote reliability and safety Bits are 10 inch length, standard 5/8-11 threaded nuts and easily attach to most hand-held drills Available in 6000 maximum/2300 minimum RPM Measures 1-1/2 inches diameter Dry premium core bits are specifically designed to tackle a variety of soft brick and concrete block drilling operations They feature laser-welded technology and inventive bar-slot cooling to promote efficiency, reliability and safety Dry cutting bits are 10-Inch in length, come with standard 5/8-Inch - 11 threaded nuts and easily attach to most hand-held drills Available in 6000 maximum/2300 minimum RPM Measures 1-1/2-Inch diameter