The Seiko Y131-0020 is a watch model based on the Y131 movement.
Parts List
| 320N50AN00 | crystal |
| 45N52NF1 | crown |
| 45N52NC1 | crown |
| 056ME | band - metal band |
| JC74A | band - band |
| JC73A | band - band |
| 0354787 | others - winding stem |
| 13C18DBM | others - minute hand |
| 13C18DBH | others - hour hand |