The Seiko 7T42-7A20 is a watch model based on the 7T42 movement.
Parts List
| 305W28HN01 | crystal |
| 40M92NA1 | crown |
| 40M92NS1 | crown - crown |
| 0351580 | crown - winding stem |
| 45M96NS1 | crown - crown - other pos. weiss |
| 45M96NA1 | crown - crown |
| 0A2930B01 | case back gasket |
| 86581801 | crystal gasket |
| 86581800 | crystal gasket |
| 80603189 | pusher |
| EC0060B01 | pusher - pusher gasket |
| 80603181 | pusher |
| ZPA73S | band |
| ZPJ87G | band |
| 03E18RK | hand - small hand (9h) |
| 04E40CG | others - small hand (6h) |
| 04E40CK | others - small hand (6h) |
| 03E18HG | others - small hand (9h) |
| 0866602 | others - holding ring for dial |
| 0878527 | others - date dial |
| 0878536 | others - date dial |
| 7T424 | others - machine code |
| 7T427A20 | others - case back |
| 7T427A2061 | others - case |
| 7T427A2075 | others - case |
| 7T427A3LXB13 | others - dial |
| 7T427A4LX914 | others - dial |
| 84321763 | others - dial ring |
| 84321764 | others - dial ring |
| A180BS | others - push pin |
| 81350540 | others - button spring |
| EG0060B01 | others - button gasket |
| 81400900 | others - button spring clip |
| 04Y06AKH | others - hour hand |
| 13SC06PW | others - second hand |
| 0Z0060B01 | others - crown and stem gasket |
| 81400829 | others - button spring clip |
| 2AB125L4BLS | others - minute hand |
| 12C54KGM | others - minute hand |
| 13SC06LC | others - second hand |
| 04Y06FGH | others - hour hand |
| 12C54LSM | others - minute hand |
| 1AB080L4BLS | others - hour hand |
| 12C54LSH | others - hour hand |
| 1AB080L4BLD | others - hour hand |
| 12C54KGH | others - hour hand |
Caliber 7T42
Other models with the same movement
| 7T42-6A00 |
| 7T42-6A0A |
| 7T42-6A0B |
| 7T42-6A10 |
| 7T42-6A20 |
| 7T42-6A49 |
| 7T42-6A50 |
| 7T42-6A5A |
| 7T42-6A60 |
| 7T42-6A6A |
| 7T42-7A00 |
| 7T42-7A10 |
| 7T42-7A2A |
| 7T42-7A39 |
| 7T42-7A40 |
| 7T42-7A4A |
| 7T42-7A4B |
| 7T42-7A50 |
| 7T42-7A5A |
| 7T42-7A5B |
| 7T42-F010 |
| 7T42-F01A |