DEWALT Diamond Core Bits are durable and efficient, with optimised diamond segment design offer the combination of high drilling speed and long life in a wide range of materials. Laser welding prevents segment loss when drilling. Standard 1 1/4 female thread for easy fitment to DEWALT and other diamond drill brands. Diameter: 78 mm Connector: 1 1/4″ Length: 350 mm D78X1 1/4″ UNC (F)XL500XT3.5MMXW10