The Seiko 4N20-1090 is a watch model based on the 4N20 movement.
Parts List
| 180W69S20A | crystal - crystal |
| 30M81NN4 | crown |
| 0F150BA1S | case back gasket - case back gasket |
| AC004BA11 | case back gasket - crown and stem gasket |
| D0N8CZ | band - band |
| 2CE060L0BDG | others - minute hand |
| 0351155 | others - winding stem |
| 81606439 | others - bracelet fixing pin |
| 81190055 | others - bracelet fixing pipe |
| 81611939 | others - bracelet fixing pin |
| 82841070 | others - case ring |
| 4N2010907EA | others - case |
| 4N201090 | others - case back |
| 4N201870XS15 | others - dial |
| 4N2061 | others - machine code |
| 1CE040L0BDG | others - hour hand |