Carbide Inserts Internal Turning Lathe Grooving Holder MGIVR2016 2520 3125 3732. Name: Screw slotting turning tool. Imported matrix, tool rod imported 40Cr material. No insert :there is only one tool bar and wrench in the package. If you choose both insert and holder, you will receive 10pcs insert, 1pcs holder and wrench.