The Seiko 5Y31-5C20 is a watch model based on the 5Y31 movement.
Parts List
| REJN37JV01 | crystal |
| REJN37JV | crystal |
| 30N97NN1 | crown |
| 0H2650B01 | case back gasket |
| 0H2650B0 | case back gasket |
| DZ0065B01 | case back gasket - button gasket |
| M1032G | band |
| 3BA075F1BNG | others - second hand |
| 07SC17NG | others - second hand |
| 06T07DGH | others - hour hand |
| 0351671 | others - winding stem |
| 06T07DGM | others - minute hand |