The Seiko 2B31-0020 is a watch model based on the 2B31 movement.
Parts List
| 180A02LN03 | crystal |
| ES5W36GN00 | crystal |
| 35NM1NN1 | crown |
| 35NM1NS1 | crown |
| 0G1700B01 | case back gasket |
| 0G1750B01 | case back gasket |
| DZ0065B01 | case back gasket - button gasket |
| M5046G | band - metal band |
| M5046S | band - metal band |
| M5047G | band - metal band |
| M5047G-BK3G | clasp - clasp |
| M5046G-BK3G | clasp - clasp |
| 08P95NGH | hand - hour hand |
| 1AE052L0BN2 | hand - hour hand |
| 3BA075F1BNG | others - second hand |
| 3BA075F1BNS | others - second hand |
| 07SC17NG | others - second hand |
| 1AA050A1BAA | others - hour hand |
| 07SC17NS | others - second hand |
| 2AE075L0BNG | others - minute hand |
| 2AA075A1BNS | others - minute hand |
| 2B31002025 | others - case |
| 2B3100202E | others - case |
| 2B310090XG14 | others - dial |
| 2B310090XN14 | others - dial |
| 2B310090XS13 | others - dial |
| 2B310100XG14 | others - dial |
| 2B310100XS13 | others - dial |
| 2B310110XS19 | others - dial |
| 2B310120XS19 | others - dial |
| 2B310130XB14 | others - dial |
| 2B310130XG14 | others - dial |
| 2B310130XR14 | others - dial |
| 2B310130XS14 | others - dial |
| 2B310140XB14 | others - dial |
| 2B310140XG14 | others - dial |
| 2B310140XR14 | others - dial |
| 2B310140XS14 | others - dial |
| 2B310250XG14 | others - dial |
| 2B310260XB14 | others - dial |
| 2B310260XG14 | others - dial |
| 2B310260XR14 | others - dial |
| 2B3126 | others - machine code |
| 82812910 | others - case ring |
| B090AS | others - push pin |
| 08P07NGM | others - minute hand |
| 1AA050A1BNG | others - hour hand |
| 2AA075A1BNG | others - minute hand |
| 07P37DGM | others - minute hand |
| 07P37DGH | others - hour hand |
| 08P07NSM | others - minute hand |
| 08P95NGM | others - minute hand |
| 2AA075A1BAA | others - minute hand |
| 1AA050A1BNS | others - hour hand |
| 08P61AHM | others - minute hand |
Caliber 2B31





Other models with the same movement
| 2B31-0010 |
| 2B31-5000 |
| 2B31-5010 |
| 2B31-5039 |