The Seiko 4M21-0A90 is a watch model based on the 4M21 movement.
Parts List
| 280A14SR01 | crystal - crystal |
| 8M35A4SNGA | crown - crown |
| 0F260NA1S | case back gasket - case back gasket |
| 80607841 | pusher - button |
| DC09BW | band - band |
| DC08BW | band - band |
| 12ST08CG | others - second hand |
| 1BA080A1BAA | others - hour hand |
| 1BB080L0BCL | others - hour hand |
| 2BA120A1BCA | others - minute hand |
| 2BB120L4BCC | others - minute hand |
| 0351552 | others - winding stem |
| 82837180 | others - case ring |
| 81400709 | others - button spring clip |
| 4M210B10XG14 | others - dial |
| 4M210B20XS14 | others - dial |
| 4M211 | others - machine code |
| A180BS | others - push pin |
| 4M210A9093 | others - case |
| AD006BA12 | others - crown gasket |
Caliber 4M21
Other models with the same movement
| 4M21-0010 |
| 4M21-0A10 |
| 4M21-0A20 |
| 4M21-0A30 |
| 4M21-0A40 |
| 4M21-0A50 |
| 4M21-0A60 |
| 4M21-0A70 |
| 4M21-0A80 |
| 4M21-0B00 |
| 4M21-0B0A |
| 4M21-0B10 |
| 4M21-0B20 |
| 4M21-0B30 |
| 4M21-0B40 |
| 4M21-0B50 |
| 4M21-0B60 |
| 4M21-0B70 |
| 4M21-0B80 |
| 4M21-0B90 |
| 4M21-0C00 |
| 4M21-0C10 |