M6 x 1.0 Thread Repair Tool Stainless Helicoil Wire Insert Set 25pc. Thread inserts material: Stainless steel. Thread tap and the drill material: HSS (High-speed Steel). Thread size: M6 X 1.0mm. The installation tools in this kit are made of high speed steel for excellent handling, while the inserts are stainless steel for increased strength and longevity.