AVAILABLE IN REGULAR, PLUG LITE and PLUG LITEST
(slightly thinner, smaller, shorter and more flexible for more low profile fit)
Plug style seat mount. Designed to help mount the new Loveseat as low as possible to the frame. Will work with other types of seats.
3/16” thick (or the plug lite is 1/8") nickel plated or parkerized.Comes with o rings to fit tight to a stock ID Panhead or knucklehead rigid frame seat post bushing but you may need to add extras if your bushing is worn or missing. 
Seat post bushings also available 
This will technically fit in a shovelhead frame without the o-rings. But you might need to spend 30 minutes with a file. The OD of the plug tube is 1.125"