Hitachi 18020 O-Ring Parts Kit for NR90AD Nailer Rings and gaskets needed to do a basic overhaul of the NR90AD All genuine Hitachi parts Includes a diagram how to install these parts in the nailer Will fix the NR90AD's air leak or slow operation Comes with a 90-day limited warranty Includes all the rings and gaskets needed to do a basic overhaul of the NR90AD This repair kit includes all genuine Hitachi parts Includes a diagram how to install these parts in the nailer Will fix the NR90AD's air leak or sluggish operation Comes with a 30-day limited warranty