The Seiko 3F31-5020 is a watch model based on the 3F31 movement.
Parts List
| SA1A93SN02 | crystal - crystal |
| 30N99NA1 | crown - crown |
| 0F195BAA1 | case back gasket |
| W048CM | band - band |
| 07T61DHH | others - hour hand |
| 07T61DHM | others - minute hand |
| 81604259 | others - bracelet fixing pin |
| 81190875 | others - bracelet fixing pipe |
| 81190155 | others - bracelet fixing pipe |
| 81607759 | others - bracelet fixing pin |
| 3F31502098A | others - case |
| 82872110 | others - case ring |
| 3F315020 | others - case back |
| 3F31502098B | others - case |
| 3F31502098C | others - case |
| 3F31502098D | others - case |
| 3F31502098E | others - case |
| 3F310100XS14 | others - dial |
| 3F311 | others - machine code |
| DZ0040B01 | others - crown and stem gasket |
| 3DA070AABDG | others - second hand |