Dewalt diamond core bit is designed for high-speed drilling and long life in a wide range of building materials. For use with diamond drills. Standard 1-1/4 Inch UNC female fitment to allow usage with Dewalt and other diamond drill brands. Length (mm): 500mm, Outer Dia. (mm): 127, Spindle Thread Size: 1 1/4 Inch UNC(F), For use With: For use with diamond drills, Application: For dry drilling clean large diameter holes in masonry and stone. Model: D127X1 1/4″ UNC(F)XL500XT3.5MMXW10