The Seiko 3B21-0AA0 is a watch model based on the 3B21 movement.
Parts List
| 210P22SB0A | crystal - crystal (sapphire) |
| 220P22SB0A | crystal - crystal (sapphire) |
| 210P22SB0B | crystal - crystal (sapphire) |
| FE238BAD2 | case back gasket - case back gasket |
| 86584060 | crystal gasket - plastic gasket for crystal |
| 80609909 | pusher - button (4h) |
| 80609949 | pusher - button |
| 80609901 | pusher - button (4h) |
| 80609941 | pusher - button |
| DFZ6BW | band - band |
| D378DG-LK00 | band - link |
| D378DG | band - band |
| D378DG-BK00 | clasp - clasp |
| 1BH057L0BDN | others - hour hand |
| 2BH090L2BDN | others - minute hand |
| 3BA090F2BNN | others - second hand |
| 1BH057L0BDZ | others - hour hand |
| 2BH090L2BDZ | others - minute hand |
| 3BA090F2BNZ | others - second hand |
| 1BH057L0BD2 | others - hour hand |
| 2BH090L2BD2 | others - minute hand |
| 3BA090F2BNG | others - second hand |
| 3B210AA0 | others - case back |
| 86585460 | others - plastic gasket for crystal |
| 3B210AA002A | others - case |
| 81351169 | others - button spring(4h) |
| 3B210AA001A | others - case |
| AC006BAD1 | others - crown and stem gasket |
| 83200273 | others - button spring clip |
| 81351630 | others - button spring |
| 3B210AA003A | others - case |
| D378DG-BKPP | others - spring bar for buckle/clasp |
| D378DG-LKPN | others - pin for link |
| S130BS | others - push pin |
| 0351511 | others - winding stem |
| DC010BAD2 | others - crown and stem gasket |