Size K45. Fits Model S with 19” tires. Brand new, unopened. I received these as a warranty replacement set. Will include the old set as well as a backup. One piece in the old set is fully functional. The other piece has 1 broken link. If you’re good at this stuff, you might be able to fix it. In addition to included lug nut adapters, also including an additional 21mm lug nut adapter set. Amazon.com: Konig K-Summit Low-Profile Passenger Car Snow Chain, Size K45 (Sold in pairs): Automotive Amazon.com: Konig K-Summit 21 mm Lug nut adapter Snow Chain Lug Nut Adapter: Automotive $250 OBO Pick up in South Palo Alto or Redwood City.