The Seiko 3B21-0AJ0 is a watch model based on the 3B21 movement.
Parts List
| D3D2DG | band - metal band |
| D3D2DG-LK00 | band - link |
| D3D2DG-BK00 | clasp - clasp |
| 81600055 | others - bracelet fixing pipe |
| D3D2DG-LKPC | others - pipe for link |
| D3D2DG-LKPN | others - pin for link |
| D3D2DG-BKPP | others - spring bar for buckle/clasp |
| 81604259 | others - bracelet fixing pin |
| 81190055 | others - bracelet fixing pipe |