Superior Parts SP KN70164C Aftermarket Piston Driver without O-ring for Max SN883RH2 - (Japanese Carbide Blade) - KN70164 & KN70091 Japanese Carbide Blade SKH-9 and Heat Treated to Rockwell C Hardness 64-66 Typically used in making professional grade dies, taps, punches and tooling In field tests it lasts significantly longer than the US S7 Steel Aerospace grade number 2024 Aluminum piston Mechanically locked piston driver interface