The Seiko B337-4020 is a watch model based on the B337 movement.
Parts List
| ES2W82GM01 | crystal - crystal |
| 35M82NA1 | crown - crown |
| 0A1800B01 | case back gasket |
| 86562000 | crystal gasket - plastic gasket for crystal |
| DL37A | band - band |
| A110BS | others - push pin (for mb) |
| 89900580 | others - spacer |
| B3379 | others - machine code |
| B337402075 | others - case |
| 0354850 | others - winding stem |
| 0Z0060B01 | others - crown and stem gasket |
Other models with the same movement
| B337-4000 |
| B337-400A |
| B337-4010 |
| B337-401A |
| B337-401B |
| B337-401C |
| B337-4030 |
| B337-5000 |
| B337-5009 |
| B337-5010 |
| B337-5020 |
| B337-5030 |
| B337-5050 |
| B337-5060 |
| B337-5070 |
| B337-5080 |
| B337-5089 |
| B337-5090 |
| B337-5100 |
| B337-6000 |
| B337-6010 |