The Seiko 4N21-5180 is a watch model based on the 4N21 movement.
Parts List
| ES0P23SN03 | crystal - crystal |
| 6K30A1SNG0 | crown |
| 0F185BAA3 | case back gasket - case back gasket |
| AC004BAA1 | case back gasket - crown and stem gasket |
| 86593810 | crystal gasket - plastic gasket for crystal |
| DA69BW | band - band |
| MK07G | band - leather band |
| 2BG062LABDG | others - minute hand |
| 1BG042LABDG | others - hour hand |
| 3BA075F1BNG | others - second hand |
| A130AS | others - push pin (for lb) |
| 4N211140XG14 | others - dial |
| 4N211140XS14 | others - dial |
| 4N211141XG14 | others - dial |
| 4N2151806R | others - case |
| 4N2164 | others - machine code |
| 4N2151806M | others - case |
| 82861230 | others - case ring |
| 4N215180 | others - case back |
| 0351155 | others - winding stem |
| 1BG042LABCA | others - hour hand |
| 2BG062LABCA | others - minute hand |