The Seiko Y131-8020 is a watch model based on the Y131 movement.
Parts List
| 291T02ANS0 | crystal |
| 291T02ANG0 | crystal |
| 35MB0NC1 | crown |
| 35MB0NF1 | crown |
| 0H2520B01 | case back gasket |
| GL72B | band - leather band |
| GL73B | band - leather band |
| A200BS | others - push pin |
| 0354786 | others - winding stem |
| EZ0058B01 | others - crown and stem gasket |