The Seiko 4N21-0490 is a watch model based on the 4N21 movement.
Parts List
| 160A02S20A | crystal |
| 30M91NA1 | crown |
| 6M30A7NNG1 | crown - crown |
| 0F140BAA3 | case back gasket - case back gasket |
| DZ39B | band - metal band |
| 2BC060A1BNG | others - minute hand |
| 1BC042A1BNG | others - hour hand |
| 3BA075F1BNG | others - second hand |
| DZ0040B01 | others - crown and stem gasket |
| 0351155 | others - winding stem |
| 81606439 | others - bracelet fixing pin |
| 81182699 | others - bracelet fixing pipe |
| 81609399 | others - bracelet fixing pin |
| 82833415 | others - case ring |
| 4N210490 | others - case back |
| 4N2104907H | others - case |
| 4N210930XS14 | others - dial |
| 4N2164 | others - machine code |
| 81116579 | others - pipe |