The Seiko 3B21-0AY0 is a watch model based on the 3B21 movement.
Parts List
| DA2E1MM | band - metal band |
| DA2E2MMLK | band - link |
| DA2E1MMLK | band - link |
| DA2E2MM | band - metal band |
| H18H12SD00B | clasp - clasp |
| H18H12SD01B | clasp - clasp |
| S130BS | others - push pin |
| DA2E1MMEP | others - endpiece |
| 81190875 | others - bracelet fixing pipe |
| 81601489 | others - bracelet fixing pin |
| DA2E2MMEP | others - endpiece |