This is a replacement for the tailgate damper accessory kit. The tail gate even being made of aluminum is really heavy especially when installed with more accessories like the tailgate step resulting to the tailgate dropping right out of the hands when opening. This kit safely lowers the tailgate in a slow and controlled manner. Having a tailgate assist when opening is a nice thing. Although some of the F-150s came with it as a factory option. Most did not. This kit installs seamlessly and hidden behind the tail lights.This tailgate damper kit can be installed easily in the passenger side and will require you to remove two T50 bolts to remove and replace the roller. The damper shock or strut installs behind the passenger tail light and the angled part of the damper shock snaps into the mount from the bed while the straight part mounts into the new roller that came with the kit. Ensure that the tailgate harness under the tailgate just above the spare tire is removed before removing the tailgate and be careful in removing the tailgate because it is heavy and may require some assistance in doing so. Fits the following vehicles: 2015 F-150 2016 F-150 2017 F-150 2018 F-150 2019 F-150 Replaces part numbers: FL3Z-99406A10-A, FL3Z99406A10A This is a compatible replacement part manufactured by AA Ignition. This tailgate damper kit is NOT a genuine OEM part. Vehicle makes and their associated vehicle models and part numbers are used in this listing only to identify the vehicles this tailgate damper kit fits.