The Seiko Y101-5420 is a watch model based on the Y101 movement.
Parts List
| SACN80GN00 | crystal |
| 35M98NF1 | crown |
| 0A2600B01 | case back gasket |
| 0G0055B01 | case back gasket - crown and stem gasket |
| GK85A | band - leather band |
| 0354765 | others - winding stem |
| A180BS | others - push pin |
| 09T50ABH | others - hour hand |
| 09T50ABM | others - minute hand |