The Seiko 8Y21-5040 is a watch model based on the 8Y21 movement.
Parts List
| BA6N93JN01 | crystal |
| 35NJ7NN1 | crown |
| 0H2600B01 | case back gasket - case back gasket |
| G1486G | band |
| G1383G | band |
| G1486G-BK5G | clasp - clasp |
| 3BA125F1BNG | others - second hand |
| DA007BA11 | others - crown and stem gasket |
| 0351112 | others - winding stem |
| 82739510 | others - case ring |
| 8Y210340XB14 | others - dial |
| 8Y210340XG14 | others - dial |
| 8Y215040 | others - case back |
| 8Y21504025A | others - case |
| 8Y2183 | others - machine code |
| A160BS | others - push pin |
| 09SC31NG | others - second hand |
| 08SC29NG | others - second hand |
| 2AF085L0BNG | others - minute hand |
| 09P53NGM | others - minute hand |
| 08PH7NGM | others - minute hand |
| 1AF055L0BNG | others - hour hand |
| 09P53NGH | others - hour hand |
| 09P37NGH | others - hour hand |
Caliber 8Y21
