The Seiko 4N00-1021 is a watch model based on the 4N00 movement.
Parts List
| 185A02JNO2 | crystal |
| ES3A47J20A | crystal - crystal |
| ES3A47J20B | crystal - crystal |
| ES3A49J20A | crystal - crystal |
| 6M30B5NNG0 | crown - crown |
| 6M30B9NNGI | crown |
| OF150BAA5 | case back gasket |
| OH1400B01 | case back gasket |