The Seiko 3F31-5A20 is a watch model based on the 3F31 movement.
Parts List
| ESDW46SV01 | crystal - crystal |
| 25M20NA3 | crown |
| 0F190NA1S | case back gasket - case back gasket |
| DA25BW | band - band |
| 2AF065L0BCF | others - minute hand |
| 1AF042L0BCF | others - hour hand |
| 07SC06DG | others - second hand |
| 0354735 | others - winding stem |
| 3F315A2075 | others - case |
| 82835640 | others - case ring |
| 3F315A20 | others - case back |
| 3F315A2075A | others - case |
| 3F315A2075B | others - case |
| 3F310C40XG14 | others - dial |
| 3F311 | others - machine code |
| A120AS | others - push pin |
| EZ0035B01 | others - crown and stem gasket |