The Seiko 4N21-0690 is a watch model based on the 4N21 movement.
Parts List
| 260P51S20A | crystal |
| 260P51S20B | crystal |
| 30M91DA1 | crown |
| 30M91NS1 | crown |
| 0F150BAA5 | case back gasket - case back gasket |
| 0F220BAA3 | case back gasket - case back gasket |
| 86569450 | crystal gasket - plastic gasket for crystal |
| 81506139 | band - bracelet fixing pin |
| 81606055 | band - bracelet fixing pin |
| B1886 | band - metal band |
| B1887 | band - metal band |
| 3EA110A0BDS | others - second hand |
| 81181859 | others - bracelet fixing pipe |
| 82842430 | others - case ring |
| 4N210690 | others - case back |
| 4N21069061 | others - case |
| 4N210690SA | others - case |
| 4N211360XN13 | others - dial |
| 4N211360XS14 | others - dial |
| 4N2164 | others - machine code |
| 1BA075A1BNG | others - hour hand |
| 81613551 | others - decorative pin |
| 81613559 | others - decorative pin |
| 82282459 | others - bezel |
| 82282459G | others - bezel |
| 0351156 | others - winding stem |
| DZ0040B01 | others - crown and stem gasket |
| 1BA075A1BNS | others - hour hand |
| 2BA110A1BNG | others - minute hand |
| 2BA110A1BNS | others - minute hand |
| 3DA110AAA7S | others - second hand |
| 3DA110AAADG | others - second hand |
| 3EA110A0BDG | others - second hand |