The Seiko 4N20-5180 is a watch model based on the 4N20 movement.
Parts List
| RE0A21JN02 | crystal - crystal |
| 35NM9NS1 | crown - crown |
| 0H2800B01 | case back gasket - rotating bezel gasket |
| HK45C | band - leather band |
| A130AS | others - push pin (for lb) |
| 4N200610XB19 | others - dial |
| 4N200610XS29 | others - dial |
| 4N205180 | others - case back |
| 4N2051802E | others - case |
| 4N2061 | others - machine code |
| 82843470 | others - case ring |
| 05Y47ANH | others - hour hand |
| DZ0040B01 | others - crown and stem gasket |
| 0351155 | others - winding stem |
| 05Y47CNM | others - minute hand |
| RE0A21JN02 | crystal - crystal |
| 35NM9NS1 | crown - crown |
| 0H2800B01 | case back gasket - rotating bezel gasket |
| HK45C | band - leather band |
| A130AS | others - push pin (for lb) |
| 4N200610XB19 | others - dial |
| 4N200610XS29 | others - dial |
| 4N205180 | others - case back |
| 4N2051802E | others - case |
| 4N2061 | others - machine code |
| 82843470 | others - case ring |
| 05Y47ANH | others - hour hand |
| DZ0040B01 | others - crown and stem gasket |
| 0351155 | others - winding stem |
| 05Y47CNM | others - minute hand |