The Seiko 2P21-520A is a watch model based on the 2P21 movement.
Parts List
| ESCW01HM01 | crystal |
| ESCW01HM02 | crystal |
| ESCW01HM | crystal |
| 30M57NA1 | crown - crown |
| 0Z0034B01 | case back gasket - crown and stem gasket |
| 0F140BAA | case back gasket |
| 0F140BAA3 | case back gasket - case back gasket |
| Z5244C | band - metal band |
| Z5244G | band - metal band |
| Z5244G-BK5G | clasp - clasp |
| Z5244C-BK5S | clasp - clasp |
| 05T11DCM | hand - minute hand |
| 2BA050A1BDG | hand - minute hand |
| 2BA055A1BDG | hand - minute hand |
| 06SC15NG | others - second hand |
| 3BA075F1BNG | others - second hand |
| 1BA037A1BNG | others - hour hand |
| 2P210510XB14 | others - dial |
| 2P210510XG14 | others - dial |
| 2P215200 | others - case back |
| 2P21520A75 | others - case |
| 2P21520ASA | others - case |
| 2P219 | others - machine code |
| 82812690 | others - case ring |
| A100AS | others - push pin |
Caliber 2P21
