The Seiko Y131-638A is a watch model based on the Y131 movement.
Parts List
| 265N06LN01 | crystal |
| 35MB0NF1 | crown |
| 0H2395N01 | case back gasket |
| 320LB | band - leather band |
| 322LB | band - leather band |
| A160BS | others - push pin |
| 0354786 | others - winding stem |
| EZ0058B01 | others - crown and stem gasket |
| 13SC04A2 | others - second hand |
| 11CR0FGM | others - minute hand |
| 11CR0FGH | others - hour hand |
| 11CR0NGM | others - minute hand |
| 11CR0NGH | others - hour hand |