The Seiko 1F21-0K90 is a watch model based on the 1F21 movement.
Parts List
| 220A02SN02 | crystal - crystal (sapphire) |
| 6M35B7SNG1 | crown - crown |
| 6M35B7SNW1 | crown - crown |
| 0F210NA1S | case back gasket - case back gasket |
| DC29AB | band - band |
| DC26BB | band - band |
| DC28AB | band - band |
| 3BA090F1BA6 | others - second hand |
| 2BA090A1BAM | others - minute hand |
| 1BA065A1BAM | others - hour hand |
| DZ0040B01 | others - crown and stem gasket |
| 1F210K907L | others - case |
| 1F211J20XS14 | others - dial |
| 1F215 | others - machine code |
| A140AS | others - push pin |
| 0351807 | others - winding stem |
| 1F210K9075 | others - case |
| 82838220 | others - case ring |
| 1F210K90 | others - case back |
| 1F210K907E | others - case |