I'm sorry I made a mistake on the hand written inventory list I made. On my good Kerr I put 6227, on my daughters list it was 6221. I went to the vault to put a couple of recent purchases in and I checked and it is 6221, and my old Kerr is 34xx it needs some parts replaced. Sorry i'm getting old and forgetful.The patent numbers on both of mine are on the lower left side and both have the anchors on them. Thanks for you understanding. Larry