CS Unitec's Threaded Diamond Core Drills and Barrels are designed for deep hole drilling in concrete with any portable diamond core drilling rig. They consist of a threaded diamond crown, threaded core barrel and threaded cap. Threaded bits, barrels and caps are available in 1- to 10-in. diameters. Threaded barrels come in lengths of 12, 24, 36, and 48 in.