The Seiko 2P21-001A is a watch model based on the 2P21 movement.
Parts List
| 180W23HN01 | crystal |
| 180P01HN03 | crystal - crystal |
| 32M39NA1 | crown |
| 0Z0034B01 | case back gasket - crown and stem gasket |
| 0F140BAA1 | case back gasket |
| 86573691 | crystal gasket - plastic gasket for crystal |
| 86560210 | bezel gasket - plastic gasket for bezel |
| Z5177G | band - metal band |
| Z5177G-BK5G | clasp - clasp |
| 1BE040L0BDG | others - hour hand |
| 3BA075F1BNG | others - second hand |
| 06SC11NG | others - second hand |
| A100AS | others - push pin |
| 2P21001A75 | others - case |
| 2P210070XB16 | others - dial |
| 2P219 | others - machine code |
| 82331611 | others - bezel |
| 82733490 | others - case ring |
| 06T01DGM | others - minute hand |
| 06T01DGH | others - hour hand |
Caliber 2P21
