1,technology support for using bits by cnc engraving machine 2,it is good for engraving 3D finishing Specification: Model Shk(mm)Ced ... head66 6V shape head66206Features Strong, durable, longer life than electroplated diamond toolGood For1. stone monument, tombstone, and so on... carving work ... , marble, malmstone and so on... Hard and fragile materials procession. Diamond engraving bit