The Seiko 3Y03-0120 is a watch model based on the 3Y03 movement.
Parts List
| 195W85HN01 | crystal |
| 195W85HN | crystal |
| 35E57NS1 | crown |
| 35E57NA1 | crown |
| AC004BAA | case back gasket |
| FH2030B04 | case back gasket |
| AC004BAA1 | case back gasket - crown and stem gasket |
| 86174340 | crystal gasket |
| 86170210 | bezel gasket |
| G5141C-LKG | band - link |
| G5141S | band |
| G5141G | band |
| G5141C | band |
| G5141C-PB1 | clasp - parts for buckle/clasp |
| G5141C-BK1S | clasp - clasp |
| 3BA125F1BNG | others - second hand |
| 3BA125F1BNS | others - second hand |
| A100BS | others - push pin (for mb) |
| 0801939 | others - date dial |
| 0884155 | others - holding ring for dial |
| 3Y030120 | others - case back |
| 3Y03012098 | others - case |
| 3Y03020LXS14 | others - dial |
| 3Y03021LXS19 | others - dial |
| 82342971 | others - bezel |
| 82820190 | others - case ring |
| 0351546 | others - winding stem |
| 08T53AGH | others - hour hand |
| 07SC51NG | others - second hand |
| 07SC51NS | others - second hand |
| 08S81LSM | others - minute hand |
| 08S81LGM | others - minute hand |
| 08T77CGM | others - minute hand |
| 08S81LSH | others - hour hand |
| 08S41BHM | others - minute hand |
| 08T47AGM | others - minute hand |
| 08S81LGH | others - hour hand |
| 08T77CGH | others - hour hand |
| 08S41BHH | others - hour hand |