The Seiko 4N21-5020 is a watch model based on the 4N21 movement.
Parts List
| ESFW13JN01 | crystal - crystal |
| 30M57NA1 | crown - crown |
| 0F160BA1S | case back gasket - case back gasket |
| 0F160BAA5 | case back gasket - case back gasket |
| AC004BA11 | case back gasket - crown and stem gasket |
| KA05A | band - band |
| KA05A-BK00 | clasp - clasp |
| 3BA075F1BNG | others - second hand |
| 07SC43NG | others - second hand |
| A110BS | others - push pin (for mb) |
| 4N210140XB14 | others - dial |
| 4N210140XG14 | others - dial |
| 4N2160 | others - machine code |
| A110AS | others - push pin |
| 0351155 | others - winding stem |
| 4N21502075 | others - case |
| 82833370 | others - case ring |
| 07T07DGM | others - minute hand |
| 1BA047A1BNG | others - hour hand |
| 2BA070A1BDG | others - minute hand |
| 2BA070A1BNG | others - minute hand |