For use with miniature drills. Lock this adapter in the chuck to convert it for precise drilling. Also adapts 3/32\" (2.40mm) Collets on rotary tools and flexible shafts to a more useful 0 to 3/32" (0 to 2.40mm). Comes with two sets of jaws Capacity 0 to 1/16" (0 to 1.60mm) and 1/16" to 3/32" (1.60mm - 2.40mm)