Cutter Hub Assembly 4 inch with Bearing support has 125 saw tooth cutters with female 5/8 -11 thread and made from high grade hardened steel. Ready to install on 4 inch Rotopeen. Saw tooth star cutter measures 1 1/4 inch with a 5/8 inch hole made from high grade hardened steel. For removing mastic and other heavy coatings. Comes with a cutter hub and 125 preloaded cutters. Cutter hubs are used with 2 inch and 4 inch Air powered or Electric Rotopeens, Aargo Tool part # 904038 and # 904015 and # 904007 and # 904039 can be ordered separately.