The Seiko 5P31-5120 is a watch model based on the 5P31 movement.
Parts List
| ESBW31SN01 | crystal |
| 32M25NA1 | crown - crown |
| 0F230BAA3 | case back gasket - case back gasket |
| 86582490 | crystal gasket |
| AK02C | band - leather band |
| 1BC070A1BAA | others - hour hand |
| 3AA125F1ANG | others - second hand |
| EB0055B01 | others - crown and stem gasket |
| 0351671 | others - winding stem |
| 5P31512075 | others - case |
| 5P315190XS19 | others - dial |
| 82811390 | others - case ring |
| A170BS | others - push pin |
| 10T19CGH | others - hour hand |
| 10T19CGM | others - minute hand |
| 10SC23T1 | others - second hand |