This part is compatible with the following machines:
Metabo HPT (Hitachi)
NV45AA Heavy Duty Coil Nailer.
NV45AB 1-3/4" Heavy Duty, Roofing Coil Nailer.
NV45AB2 Side Load Coil Roofing Nailer.
NV45AB2(S) Bottom Load Coil Roofing Nailer.
NV45AB2M 1 3/4 Inch Roofing Coil Nailer Side Load Magazine (Wire Collation)
NV45AB3 Nailer.
NV45AE 1-3/4" Side Load Coil Roofing Nailer.
NV45AES Nailer.
NV50A1 Light-Duty Coil Utility Nailer.
NV50A1M 2 Inch Utility Coil Nailer (Wire Collation)
NV50AP Nailer.
NV50AP2 Full Round Head, Coil, Wire Collation Pasti-Tacker Plus.

For install:
1.remove the retaining ring from the feeder shaft.
2.Slide the feeder with feeder spring off of the shaft.
3.The old spring can now be removed and the new one set in place.
4.Slide the feeder with spring back onto the feeder shaft and secure with the retaining ring.