The Seiko 5Y39-721A is a watch model based on the 5Y39 movement.
Parts List
| 280N32JM01 | crystal |
| 280N32JM | crystal |
| 30MA6NA1 | crown - crown |
| 0H2520N01 | case back gasket - case back gasket |
| 0G0055B01 | case back gasket - crown and stem gasket |
| 0G0055B0 | case back gasket |
| ZPJ70G | band |
| ZPJ69G | band |
| 0351670 | others - winding stem |
| 82802420 | others - case ring |
| 0801740 | others - date dial |
| 5Y39721A25 | others - case |
| 5Y397380XG14 | others - dial |
| 5Y399 | others - machine code |
| A180BS | others - push pin |
| 10T76DAH | others - hour hand |
| 10T76DAM | others - minute hand |