Bosch OSC212FH 2-1/2-inch BIM Hammerhead Plunge Blade The product is 2-1/2" Hammerhead Blade 12 Pin design provides a secure connection for high-torque oscillating tools (tools not included) Cuts and easily removes debris in abrasive woodworking materials. Maneuvers easily in wood. Patented BiM manufacturing - only manufacturer that can weld HSS onto HCS in a circular design; others can only weld in a straight and linear fashion