Upgrade. they rust. Not many, but they are there. Rust in just 8 weeks of summer! I used 20 of these on my Charger RT and am very satisfied. Significantly cheaper than offered by the seller. Consists of one piece. The Dealer's Nut costs $9 each and comes in two parts. union nut and chrome cap. Eventually the cap will get stuck in the socket. That's the perfect size for a charger, by the way. I bought cheaper ones on eBay but the Acorn Bulge Seat was too small. God bless this seller and Revane.