The Seiko W851-4020 is a watch model based on the W851 movement.
Parts List
| SA0P55L20A | crystal - crystal (inorganic) |
| SA0P55L20B | crystal - crystal |
| SA0P55L20C | crystal - crystal (inorganic) |
| 0F309BEA1 | case back gasket - case back gasket |
| 86641070 | crystal gasket - plastic gasket for crystal |
| 86641075 | crystal gasket - plastic gasket for crystal |
| 8071173D | pusher - button (4h) |
| 80711776 | pusher - front button |
| 80711777 | pusher - front button |
| 80711778 | pusher - front button |
| 80711710 | pusher - button |
| 8071171A | pusher - button |
| 8071171C | pusher - button |
| 8071171D | pusher - button |
| 80711730 | pusher - button |
| 8071173A | pusher - button (4h) |
| 8071173C | pusher - button (4h) |
| 80711770 | pusher - front button |
| 4HU5AB | band - band |
| 4HU6AB | band - band |
| 4HU4AB | band - band |
| 4HK0AB | band - band |
| 4HK1AB | band - band |
| 4HN2AB | band - band |
| 89925030 | band - other |
| 89925390 | band - other |
| 89925396 | band - other |
| 89925397 | band - other |
| 89925398 | band - other |
| 8992543G | band - other |
| T160BS | others - push pin |
| T280ES | others - push pin |
| W85110 | others - machine code |
| W85150 | others - machine code |
| 8992543A | others - air protector unit |
| 8992543B | others - air protector unit |
| W8514020N2D | others - case |
| W8514020N2E | others - case |
| W8514020N2F | others - case |
| 86510959 | others - conducting plate |
| 86511079 | others - conducting plate |
| W8514020N2A | others - case |
| W8514020 | others - case back |
| W8514020N2B | others - case |
| W8514020N2C | others - case |
| 81351630 | others - button spring |
| AD006BA11 | others - crown and stem gasket |
| 83200219 | others - button spring clip |
| 81351859 | others - button spring (front) |
| 81518259 | others - case back screw |
Other models with the same movement