I sent a reply but wasn't sure if it would come directly to you. I am new to this chat forum and have been having trouble accessing visitor comments, basically couldn't get to them until today. Sorry. The center caps were purchased from a Toyota dealership. They are plastic and come in two sizes, these are the small ones. I think they are the same ones used on the other type of Prius wheel. Cost was about $12 each, a little pricey for a small piece of plastic but made the big difference for sure. The trim rings are from a company called Auto Amenity online. Just an fyi on those...since the wheel is alloy and not steel the edges where the clips attach are a bit thicker. The rings were not the easiest thing to get on (okay, I am a girl here) and required a rubber mallet and there is a small space between the ring and the edge but you only see it if you standing close to the car. It wasn't enough to bother me because from a distance and driving they look great
