The Seiko 1F21-0020 is a watch model based on the 1F21 movement.
Parts List
| 135W05HK01 | crystal |
| 30E33NA1 | crown |
| 0F135BAA1 | case back gasket |
| AC004BAA1 | case back gasket - crown and stem gasket |
| 86591270 | crystal gasket |
| DZ67A | band - metal band |
| 3BA075F1BNG | others - second hand |
| 0351807 | others - winding stem |
| 06SC11NG | others - second hand |
| 81606439 | others - bracelet fixing pin |
| 81181459 | others - bracelet fixing pipe |
| 81606679 | others - bracelet fixing pin |
| 1F210020 | others - case back |
| 1F210020SA | others - case |
| 1F210020XS14 | others - dial |
| 1F219 | others - machine code |
| 82832010 | others - case ring |
| 06T23DGH | others - hour hand |
| 06T23DGM | others - minute hand |