The Seiko 8S21-5010 is a watch model based on the 8S21 movement.
Parts List
| REHN33JV02 | crystal |
| REHN33JV03 | crystal |
| 35NJ1NG1 | crown |
| 35NJ1NA1 | crown |
| DH100B01 | case back gasket |
| 0H3100B01 | case back gasket |
| DH0100B01 | case back gasket - crown and stem gasket (4h) |
| 89952130 | band - other |
| Z1379F | band - metal band |
| Z1379F-LKS | band - link |
| Z1379S | band - metal band |
| Z1379S-LKS | band - link |
| Z1379S-PB1 | clasp - parts for buckle/clasp |
| Z1379S-BK1S | clasp - clasp |
| Z1379F-PB1 | clasp - parts for buckle/clasp |
| Z1379F-BK1S | clasp - clasp |
| 09PA1NGH | hand - hour hand |
| 09PA1XKH | hand - hour hand |
| 10P53XKM | hand - minute hand |
| 10SC25NR | hand - second hand |
| 3AA125F1ANG | others - second hand |
| 10P53NGM | others - minute hand |
| 82812350 | others - case ring |
| 8430839A | others - dial ring |
| 8430839B | others - dial ring |
| 8S2110 | others - machine code |
| 8S215000XA19 | others - dial |
| 8S215000XA29 | others - dial |
| 8S215010 | others - case back |
| 8S2150101B | others - case |
| 8S215010EA | others - case |
| A180BS | others - push pin |
| 3AA125F1AAR | others - second hand |
| 10SC25T1 | others - second hand |
Other models with the same movement