The Seiko 2B21-5020 is a watch model based on the 2B21 movement.
Parts List
| ESYN39AN01 | crystal |
| 35NM1NN1 | crown |
| 0G1890B02 | case back gasket - case back gasket |
| DZ0065B01 | case back gasket - button gasket |
| Z5155G | band - metal band |
| Z5156G | band - metal band |
| Z5156G-BK5G | clasp - clasp |
| Z5155G-BK5G | clasp - clasp |
| 06P01DGH | hand - hour hand |
| 06P01DGM | hand - minute hand |
| 1AG042LABNG | hand - hour hand |
| 3BA075F1BNG | others - second hand |
| 1AA040A1BNG | others - hour hand |
| 2AA060A1BNG | others - minute hand |
| 2AG062LABNG | others - minute hand |
| 06SC11NG | others - second hand |
| 2B210060XG14 | others - dial |
| 2B210070XB14 | others - dial |
| 2B214 | others - machine code |
| 2B21502025 | others - case |
| 82730510 | others - case ring |
| A110AS | others - push pin |
| 06P21NGM | others - minute hand |
| 06P21NGH | others - hour hand |
Caliber 2B21
Other models with the same movement
| 2B21-5000 |
| 2B21-5010 |