Perlick changed their manufacturing methods, so some of these no longer fit. I can't give you exact dates, but my almost two year old Perlicks fell into this category. My adapter looks exactly the same and I've been waiting since August for the shop to figure out what they are going to do. I'd call Williams to see if they can check an old and new style faucet for you. Otherwise the price is right and I'm tired of waiting.