YZ6030: High hardness, used for processing steel parts below 45 degrees. YZ15TF: Used to process stainless steel and reduce tool breakage. YZ735: used to process stainless steel and reduce tool vibration. YZ5115: Upgraded version, Good toughness, Used for processing cast iron.JC700: upgraded version of JC600, Used for processing steel parts. The product adopts screw type compression structure. Diamond compound polishing for surface treatment, fine and shiny. The cutter bar is hardened and durable. Imported base body, tool rod imported spring steel material. NO insert : there is only one tool bar and wrench in the package. NO Cutter bar : There are only 10 blades in the kit. If you choose both blade and holder, you will receive 10pc blades, 1pc holder and wrench.