These replacement blades have unique Blade Over Shaft (B.O.S.) technology to deliver an ultrashort and compact head for unmatched accuracy and penetration. Hardened Rock-Buster stainless steel tips are .040" thick with a 1-1/4" cutting diameter for increased penetration. Ultratight machining tolerance ensures perfect balance and head-to-head consistency. Includes 9 blades and 3 washers.