The Seiko 4N00-5621 is a watch model based on the 4N00 movement.
Parts List
| K00A63JN02 | crystal |
| K00A63JN | crystal |
| 6M35B3NNG0 | crown - crown |
| 35MS1NN1 | crown - crown |
| 6M35B3NN | crown |
| 0H2000B01 | case back gasket - case back gasket |
| NO | band - leather band |
| WHA33K | band |
| WHJ41K | band |
| A120BS | others - push pin (for lb) |
| 4N001691XS19 | others - dial |
| 4N001701XS19 | others - dial |
| 4N003581XS19 | others - dial |
| 4N005621 | others - case back |
| 4N00562125 | others - case |
| 4N00562125A | others - case |
| 4N0061 | others - machine code |
| 82852890 | others - case ring |
| DZ0040B01 | others - crown and stem gasket |
| 0351155 | others - winding stem |
| 08Y25AGM | others - minute hand |
| 08Y21AGH | others - hour hand |
| 08Y21AGM | others - minute hand |
| 08Y19AGH | others - hour hand |