The Seiko 1M20-5A20 is a watch model based on the 1M20 movement.
Parts List
| RE2A74SR01 | crystal - crystal |
| 8M40B8SNW1 | crown - crown |
| 0F210NA1S | case back gasket - case back gasket |
| D130AZ | band - band |
| 1CE042L0BD1 | others - hour hand |
| 2CE062L0BD1 | others - minute hand |
| 81606439 | others - bracelet fixing pin |
| 81190055 | others - bracelet fixing pipe |
| 0351555 | others - winding stem |
| 1M205A2061 | others - case |
| 82839300 | others - case ring |
| 1M205A20 | others - case back |
| 1M200A50X923 | others - dial |
| 1M201 | others - machine code |
| 81504189 | others - screw |
| AD006BA12 | others - crown gasket |
Caliber 1M20
Other models with the same movement
| 1M20-0A10 |
| 1M20-0A20 |
| 1M20-0A30 |
| 1M20-0A40 |
| 1M20-0A50 |
| 1M20-0A60 |
| 1M20-0A70 |
| 1M20-5A00 |
| 1M20-5A10 |
| 1M20-5A30 |
| 1M20-5A40 |
| 1M20-5A50 |
| 1M20-5A60 |
| 1M20-5A70 |
| 1M20-5A80 |
| 1M20-5A90 |
| 1M20-5B00 |