The Seiko 5S21-0A30 is a watch model based on the 5S21 movement.
Parts List
| 310W74JN01 | crystal - crystal |
| 45M86NA1 | crown - crown |
| 0A3100N01 | case back gasket |
| AC09A | band - band |
| AC10A | band - leather band |
| 13T06DBM | others - minute hand |
| 13SC20TB | others - second hand |
| 13T06DBH | others - hour hand |
| 82811000 | others - case ring |
| 0351684 | others - winding stem |
| 5S210A3076 | others - case |
| 5S210A30 | others - case back |
| 5S210A50XS19 | others - dial |
| 5S218 | others - machine code |
| 81350820 | others - spring |
| 81871361 | others - case bow |
| 87020380 | others - back plate |
| 0Z0060B01 | others - crown and stem gasket |
Caliber 5S21
