The Seiko 3B21-0AS0 is a watch model based on the 3B21 movement.
Parts List
| D3B2AB | band - metal band |
| D3B2AB-LK00 | band - link |
| D3B2CB | band - metal band |
| D3B2CB-LK00 | band - link |
| D3B2CB-BK00 | clasp - clasp |
| D3B2CB-BKLK-12H | clasp - parts for buckle/clasp |
| D3B2CB-BKLK-6H | clasp - parts for buckle/clasp |
| D3B2AB-BK00 | clasp - clasp |
| D3B2AB-BKLK-12H | clasp - parts for buckle/clasp |
| D3B2AB-BKLK-6H | clasp - parts for buckle/clasp |
| D3B2AB-BKPN | others - pin for buckle/clasp |
| D3B2AB-BKPP | others - spring bar for buckle/clasp |
| D3B2AB-LK01 | others - half adjust link |
| D3B2AB-LKPN | others - pin for link |
| 81606439 | others - bracelet fixing pin |
| 81190055 | others - bracelet fixing pipe |
| D3B2CB-BKPN | others - pin for buckle/clasp |
| D3B2CB-BKPP | others - spring bar for buckle/clasp |
| D3B2CB-LK01 | others - half adjust link |
| D3B2CB-LKPN | others - pin for link |