Aftermarket Hitachi Framing Nailer Piston Driver. This is a generic replacement driver with o-ring for the Hitachi NR83A, NR83A2, NR83A2(S) framing guns. This comes with a patent pending locking mechanism which will not allow the driver to unscrew from the piston. Aluminum is crimped into the unilok grooves of the shaft to prevent unscrewing. Guaranteed never to unscrew.Compatible With:NR83A2(S) Framing Nailer, Full Head, Plastic Strip Collation (without Depth Adjustment) NR83A 3-1/4" Full Head NailerNR83A3S Strip NailerNR83A3 Strip NailerNR83A2 Strip NailerNR83A5 Strip Nailer