New 10 pieces 442 Carbon steel wire brushes in cup shape They will fit your hand drill, drill press & for Dremel and Foredom tool with a 1/8" (3.175mm) collet. Overall length is 51mm (2 inch). Cup diameter is 1/2" (12.7mm). Shank diameter : 3.17mm (1/8 inch) | suitable for removing rust and oxidation. US-BASED CUSTOMER SERVICE: Available by chat, email, phone, or visit us at our customer service center in La Crosse, WI.