Diamond Concrete Core Bit Set: 1", 2", 3", 4", 5", 6", 7", 8", 9" and 10" WET coring bits for core drilling. Overall Length: 17" Approximate Inside Barrel Depth: 14.5" Approximate Thread Type: Industry Standard 1 1/4" (Directly fits our BLUEROCK Z-1 Core Drills)