Harley Knucklehead/Panhead/Flathead "Extra Heavy" Seat Post Spring Spacers

We know there were two styles of spacers used.  We understand these to be the "extra heavy" style spacers, distinguished by their squared guide ends.  In contrast, the standard style has one squared guide end while the other is tapered.

For reference, I.D. is 3/8".  O.D. is 1/2"

• Condition:   Used
• Type:   Flathead, Knucklehead, Panhead, Shovelhead
• Vintage:   1930-80

081121  D-4  (21 07 25, 6-33)