I left out the big green caps because I wanted a more subtle reminder that I was being sucked into nitrogen snake oil. It wasn't actually listed anywhere on the truck receipt, so it was probably buried in a $2,500 "dealer protection package" that took minutes to negotiate down to $300. This rating and search Fill normal vehicles with nitrogen. You'll be filling these tires with Costco air in no time. Then buy these caps to impress your uninformed friends. Remember to check your tire pressure monthly.