part number: 885-917 Package Includes: as images show, 1 Aftermarket Piston Driver Compatible with: Hitachi NR90AD NR90ADPR Mechanically locked piston driver interface Aerospace grade number 2024 Aluminum piston Heat treated tool steel 6150 Rockwell hardness 50-52 parts install quickly to make your nailer work like new again A brand-new, unused, unopened, undamaged item in its original packaging  Return refund: If you have any questions, you can refund in full without any problems