Hard to find Vintage Kluson Sealfast Ferrule, I have seen this style on a 1976 Gibson Johnny Smith and a Super 400 in pictures I found on the internet and they may have been used on some other models and other years but haven't seen too many with the large diameter flange. The inside diameter is 5/16" and the outside diameter of the flange is 5/8". Measuring with dial calipers the outside diameter of the knurled end is .390. The gold plating is nice but there are nicks from being used and being stored in a parts drawer with other parts for years I am starting this listing with 5 available and the picture is typical for the all of them. The price listed is for 1 ferrule. Thank you