There are four models, for the new 2013 Pathfinder with two wheel/tire sizes. Here is a quick summary.
Pathfinder S - 18" x 7.5" Aluminum Alloy Wheels with P235/65R18 tires.
Pathfinder SV - 18" x 7.5" Aluminum Alloy Wheels with P235/65R18 tires.
Pathfinder SL - 18" x 7.5" Aluminum Alloy Wheels with P235/65R18 tires.
Pathfinder Platinum - 20" x 7.5" Aluminum Alloy Wheels with P235/55R20 tires.