The Seiko 1221-5540 is a watch model based on the 1221 movement.
Parts List
| ESSN23JN00 | crystal - crystal (inorganic) |
| 30N63NA1 | crown - crown |
| 0H1550B01 | case back gasket |
| HS10A | band - metal band |
| 3BA075F1BNG | others - second hand |
| 1AA040A1BNG | others - hour hand |
| 2AA060A1BNG | others - minute hand |
| 06P05NGH | others - hour hand |
| 06P05NGM | others - minute hand |
| 12210780XG14 | others - dial |
| 122110 | others - machine code |
| 1221554025 | others - case |
| 82711030 | others - case ring |
| 06SC11NG | others - second hand |
| 0351117 | others - winding stem |
| T090AS | others - push pin |
| DZ0040B01 | others - crown and stem gasket |
Caliber 1221
