The Seiko 1F21-5B10 is a watch model based on the 1F21 movement.
Parts List
| SACW14SN01 | crystal |
| 25M20NS3 | crown |
| 0A1900N01 | case back gasket - case back gasket |
| MK52E | band - leather band |
| A130AS | others - push pin (for lb) |
| 1F210F20XS13 | others - dial |
| 1F215 | others - machine code |
| 1F215B10 | others - case back |
| 1F215B1061 | others - case |
| 82824000 | others - case ring |
| 0351807 | others - winding stem |
| 07SC06DS | others - second hand |
| 1BB050L0BCA | others - hour hand |
| EZ0035B01 | others - crown and stem gasket |
| 2BB075L0BCA | others - minute hand |
| 3EA075A0BDS | others - second hand |