✅ Japanese Carbide - SKH-9 ✅ Heat treated to Rockwell hardness 64-66 ✅ Aerospace grade #2024 Aluminum piston | Mechanically locked piston driver interface ✅ In field tests it lasts significantly longer than the US S7 steel Compatible With NR83A2(S) Framing Nailer, Full Head, Plastic Strip Collation (without Depth Adjustment) | NR83A 3-1/4" Full Head Nailer | NR83A3S Strip Nailer | NR83A3 Strip Nailer | NR83A2 Strip Nailer