The Seiko 4N21-0090 is a watch model based on the 4N21 movement.
Parts List
| 190WC9SN01 | crystal |
| 30M09NS5 | crown |
| 30M09NA5 | crown |
| AC004BA11 | case back gasket - crown and stem gasket |
| 0F170BAA3 | case back gasket - case back gasket |
| DK30D | band - band |
| DK33D | band - band |
| DK31D | band - leather band |
| 1BB055SCBCF | others - hour hand |
| 2BB080SEBLF | others - minute hand |
| 08T25CGH | others - hour hand |
| 08T25CGM | others - minute hand |
| 3BA125F1BNG | others - second hand |
| 3BA125F1BNS | others - second hand |
| 0351155 | others - winding stem |
| 4N21009075A | others - case |
| 4N210090 | others - case back |
| 4N21009075B | others - case |
| 82840495 | others - case ring |
| 4N2100907EA | others - case |
| 4N210230XG14 | others - dial |
| 4N210230XS13 | others - dial |
| 4N210500XG14 | others - dial |
| 4N2164 | others - machine code |
| A120AS | others - push pin |
| 07SC51NG | others - second hand |
| 08T25CSH | others - hour hand |
| 08T25CSM | others - minute hand |
| 07SC51NS | others - second hand |