1/4×20 or 1/4×28 skull bolt.
Made to fit as a Harley Davidson seat bolt.
Stainless steel hardware cast into place. Skulls are American made of a durable bone color casting resin made in the USA as well.
Antiqued with black oil base to show the details.
Same skull also made open mouth (SK034-SB) and with no mandible (SK015-SB).
1/4×20 is 1996 and newer.
1/4×28 is 1995 and older.
Bottom to top 0.919″
Front to back 1.225″
Side to side 0.630″
Stud is 0.50″ to 0.650″