This is a Mills Vest Pocket lock - make sure it is the correct replacement for your machine. I'm aware of two types of machines and only one model will accept this one. It's hard to find.
The item "Mills Vest Pocket lock" is in sale since Tuesday, July 28, 2020. This item is in the category "Collectibles\Casino\Slots\Machines\Antique Coin Slot Machines". The seller is "feld00" and is located in Morrisville, Pennsylvania. This item can be shipped to United States.