I do it with my own hands and sell covers on tanks. This lid is made specifically for the Harley Davidson motorcycle.
This cover, unlike the rest of my covers, has a special adapter for the standard neck of the Harley tank. The cover is made of aluminium, all screws are made of stainless steel, the adapter is made of aluminum. The diameter of the lid is about 70mm. To install, you need to remove the old cover and screw the adapter into the neck of the tank, from above to install the lid. There are adapters with right and left thread.
Do not forget to indicate with which thread direction you want the cover. In the photo I showed you about how it will look on the tank. The item "Custom HandMade Hammer Gas tank cap cover Harley Davidson Bobber Chopper" is in sale since Monday, October 25, 2021. This item is in the category "eBay Motors\Parts & Accessories\Motorcycle Parts\Body & Frame\Gas Tanks".
The seller is "garage_nishtyaki" and is located in Energodar. This item can be shipped worldwide.