The Seiko 4N00-0721 is a watch model based on the 4N00 movement.
Parts List
| 240A02JN02 | crystal |
| 240A02JN | crystal |
| 30MD1NN4 | crown - crown |
| 0F200BAA | case back gasket |
| 0F200BAA3 | case back gasket - case back gasket |
| WKJ25K | band |
| ZKJ29K | band - band |
| BKA34K | band - leather band |
| ZKJ30K | band |
| 2CA095A3BNG | others - minute hand |
| 1CA065A3BNG | others - hour hand |
| 0351156 | others - winding stem |
| DZ0040B01 | others - crown and stem gasket |
| 4N00072125A | others - case |
| 82860670 | others - case ring |
| 4N000721 | others - case back |
| 4N002481XB14 | others - dial |
| 4N002481XS14 | others - dial |
| 4N002491XS19 | others - dial |
| 4N002501XG14 | others - dial |
| 4N002501XS14 | others - dial |
| 4N002511XS19 | others - dial |
| 4N0061 | others - machine code |
| A140BS | others - push pin |
| 2CA095A3BAA | others - minute hand |
| 2CX095A0BAA | others - minute hand |
| 1CA065A3BAA | others - hour hand |
| 1CX065A0BAA | others - hour hand |
| 2CC100AABAA | others - minute hand |
| 1CC065AABAA | others - hour hand |