Diamond Core Drills Diamond core drills bits is designed for reliability, efficiency and safety on a variet construction materisls, it is ideal for drilling in concrete and brick work. Item Number Diameter Overall Length INCHES Metric (MM) INCHES Metric (MM) QE 060681 23/5" 68 32/5" 85 QE 060682 23/5" 68 61/2" 165 QE 060683 23/5" 68 16" 400 QE 060821 31/5" 82 32/5" 85 QE 060822 31/5" 82 61/2" 165 QE 060823 31/5" 82 16" 400