The Seiko 4N21-0450 is a watch model based on the 4N21 movement.
Parts List
| 185P01HN03 | crystal - crystal |
| 185P01SN03 | crystal - crystal |
| 6K30A1SNG0 | crown |
| 6K30A1SNW0 | crown - crown |
| 0F170BAA1 | case back gasket |
| AC004BAA1 | case back gasket - crown and stem gasket |
| 86561071 | crystal gasket |
| DA68AB | band - band |
| DA78BB | band - band |
| DA68BB | band - band |
| 3BA075F1BNG | others - second hand |
| 3BA075F1BNS | others - second hand |
| 1BA050A1BAC | others - hour hand |
| 2BA075A1BAC | others - minute hand |
| 3BA125F1BNG | others - second hand |
| A120BS | others - push pin (for lb) |
| 4N210960XG14 | others - dial |
| 4N210960XS13 | others - dial |
| 4N210961XG14 | others - dial |
| 4N210961XS13 | others - dial |
| 4N210970XS19 | others - dial |
| 4N210971XS19 | others - dial |
| 4N2164 | others - machine code |
| 4N21045075A | others - case |
| 4N21045075B | others - case |
| 4N21045071 | others - case |
| 4N210450 | others - case back |
| 4N21045075 | others - case |
| 0351155 | others - winding stem |
| 1BD050A0BAA | others - hour hand |
| 1BA050A1BAA | others - hour hand |
| 82832995 | others - case ring |
| 07T33AGH | others - hour hand |
| 07T33AGM | others - minute hand |
| 2BD075A0BAA | others - minute hand |
| 2BA075A1BAA | others - minute hand |