The Seiko 4N21-0390 is a watch model based on the 4N21 movement.
Parts List
| 175A02SN02 | crystal - crystal |
| 30M81NA4 | crown - crown |
| 30M81NS4 | crown - crown |
| 0F150BAA5 | case back gasket - case back gasket |
| 0H1600B01 | case back gasket - case back gasket |
| AC004BA11 | case back gasket - crown and stem gasket |
| DAN6AW | band - band |
| DA46AW | band - leather band |
| DA46AB | band - band |
| DK50E | band - band |
| DA46BW | band - band |
| MK30F | band - leather band |
| DA46BW-BJ00 | clasp - buckle |
| 3EA070A0BDS | others - second hand |
| 07SC29DG | others - second hand |
| 07TG6DGH | others - hour hand |
| 07TG6DGM | others - minute hand |
| 07SC29DS | others - second hand |
| 1BC047A1BAA | others - hour hand |
| 2BC070A1BAA | others - minute hand |
| 3EA070A0BDG | others - second hand |
| 1BB047A1BNG | others - hour hand |
| 1BB047A1BNS | others - hour hand |
| 2BB070A1BNG | others - minute hand |
| 2BB070A1BNS | others - minute hand |
| 0351155 | others - winding stem |
| 4N21039071B | others - case |
| 4N21039071C | others - case |
| 4N21039075A | others - case |
| 82352771 | others - bezel |
| 4N21039061A | others - case |
| 4N210780XG14 | others - dial |
| 4N210780XS13 | others - dial |
| 4N210780XS24 | others - dial |
| 4N210790XS19 | others - dial |
| 4N211350XS13 | others - dial |
| 4N211660XS13 | others - dial |
| 4N211680XS13 | others - dial |
| 4N2164 | others - machine code |
| 82352779 | others - bezel |
| A110AS | others - push pin |
| 82841030 | others - case ring |
| 4N21039071A | others - case |
| 4N210390 | others - case back |
| 1BD050A0BAD | others - hour hand |
| 07T33ASH | others - hour hand |
| 07T37ASM | others - minute hand |
| 3DA070AABDS | others - second hand |
| 3DA070AABDG | others - second hand |
| 07T27AGM | others - minute hand |