The Seiko 3Y03-0020 is a watch model based on the 3Y03 movement.
Parts List
| 190W53LN | crystal |
| 190W53LN00 | crystal |
| 32M51NN1 | crown |
| 32M51NS1 | crown |
| 0F160BAA5 | case back gasket - case back gasket |
| AC004BA11 | case back gasket - crown and stem gasket |
| 0F160BAA | case back gasket |
| 86564110 | crystal gasket - plastic gasket for crystal |
| 86170190 | bezel gasket - plastic gasket for bezel |
| B5494G | band |
| B5494G-LKG | band - link |
| B5494S | band - metal band |
| B5494S-LKS | band - link |
| B5494C | band |
| B5494S-PB1 | clasp - parts for buckle/clasp |
| B5494G-BK1G | clasp - clasp |
| B5494S-BK1S | clasp - clasp |
| B5494G-PB1 | clasp - parts for buckle/clasp |
| 08S21BGH | hand - hour hand |
| 08S21BGM | hand - minute hand |
| 08S21BSH | hand - hour hand |
| 08S21BSM | hand - minute hand |
| 07SC17NG | others - second hand |
| 07SC17NS | others - second hand |
| 1BC050A1BAA | others - hour hand |
| 3BA125F1BNG | others - second hand |
| 3BA075F1BNG | others - second hand |
| 3BA075F1BNS | others - second hand |
| A120BS | others - push pin (for lb) |
| 0801752 | others - date dial |
| 0884155 | others - holding ring for dial |
| 0351546 | others - winding stem |
| 3Y030020 | others - case back |
| 3Y03002061 | others - case |
| 3Y03002075 | others - case |
| 3Y03003LXS13 | others - dial |
| 3Y03003LXS14 | others - dial |
| 82341691 | others - bezel |
| 82341699 | others - bezel |
| 82820510 | others - case ring |
| 2BA075A1BNG | others - minute hand |
| 08SC29NG | others - second hand |
| 07T23AFH | others - hour hand |
| 07T23AFM | others - minute hand |
| 2BC075A1BAA | others - minute hand |
| 07T03NGM | others - minute hand |
| 07S11BGM | others - minute hand |
| 1BA050A1BNG | others - hour hand |
| 07S11BGH | others - hour hand |
| 07T03NGH | others - hour hand |