The Seiko 4N21-0820 is a watch model based on the 4N21 movement.
Parts List
| 190WC9S20A | crystal - crystal |
| 6M30A3NNG1 | crown - crown |
| 0F160BAA5 | case back gasket - case back gasket |
| D049CG | band - band |
| D050CG | band - band |
| 1BF052A1BNG | others - hour hand |
| 3BA075F1BNG | others - second hand |
| 1BB052A1BNG | others - hour hand |
| 2BF075A1BNG | others - minute hand |
| 0351155 | others - winding stem |
| DZ0040B01 | others - crown and stem gasket |
| 81606439 | others - bracelet fixing pin |
| 81610199 | others - bracelet fixing pin |
| 81181919 | others - bracelet fixing pipe |
| 82833515 | others - case ring |
| 4N2108207EA | others - case |
| 4N210820 | others - case back |
| 4N2108207EB | others - case |
| 4N211580XS14 | others - dial |
| 4N211590XS14 | others - dial |
| 4N2164 | others - machine code |
| 2BB075A1BNG | others - minute hand |