The Seiko 1F21-0B90 is a watch model based on the 1F21 movement.
Parts List
| 175W08SN01 | crystal |
| 30MA2NA1 | crown - crown |
| 0A1800B01 | case back gasket |
| ZB30A | band - metal band |
| 0351807 | others - winding stem |
| 81180229 | others - bracelet fixing pipe |
| 81604259 | others - bracelet fixing pin |
| 82821060 | others - case ring |
| 1F210B90 | others - case back |
| 1F210B9098 | others - case |
| 1F210D00XS14 | others - dial |
| 1F219 | others - machine code |
| EZ0035B01 | others - crown and stem gasket |
| 07TA8NGH | others - hour hand |
| 07TA8NGM | others - minute hand |
| 07SC02NA | others - second hand |