eBay
 HATTA MX-10 BMX HEAD SET.
Size 25.4mm (1”)  x 24t
Made in Japan .
Color white
Includes lock nut, lock washer, adjusting cup, head top cone, head bottom cup, crown cone and ball retainers.

This is a new never mounted in original box  head set.
Fits old school  common 1” bmx bikes from the 70s and 80s