Heavy Duty Orange Diamond Core Bore Bit for Concrete with HOL Specifications for General Purpose and Longer Life. Excellent footage and drilling speed. Designed for all types of wet drilling in applications with light to moderate steel. Very high quality diamond and longer coring life. Core Bit Lengths: 1/2in. to 7/8in. Diameter Core Bits Standard Core Length= 12in., 1in. to 14in. Diameter Core Bits Standard Core Length = 13in. For use on mounted core rigs (all sizes) and hand held motors (3in. and under). Hub Sizes: 1/2in to 1-1/2in = 5/8in-11 threaded hub. 1-5/8in and up = 1-1/4in-7 threaded hub