Superior Parts SP 885-915 Aftermarket Piston Driver for Hitachi NR83A, NR83A2 Framing Nailer (885-915, 877-323) Fits Hitachi NR83A and NR83A2 Heat treated tool steel 6150 Rockwell hardness 50-52 Aerospace grade number 2024 Aluminum piston Mechanically locked piston driver interface