The Seiko 2P21-5100 is a watch model based on the 2P21 movement.
Parts List
| RE1W19HN01 | crystal |
| 35MH3NA1 | crown |
| 0F165BAA5 | case back gasket - case back gasket |
| 86581675 | crystal gasket - plastic gasket for crystal |
| B5399G | band - metal band |
| B5400C | band - metal band |
| B5400C-BK3G | clasp - clasp |
| B5399G-BK3G | clasp - clasp |
| 05T21DGM | hand - minute hand |
| 05T23DGH | hand - hour hand |
| 3BA075F1BNG | others - second hand |
| 1BE040L0BDG | others - hour hand |
| 06SC15NG | others - second hand |
| EB0055B01 | others - crown and stem gasket |
| 2P210240XL1S | others - dial |
| 2P210250XB16 | others - dial |
| 2P215100 | others - case back |
| 2P21510075 | others - case |
| 2P2151007H | others - case |
| 2P219 | others - machine code |
| 82803070 | others - case ring |
| T080BS | others - push pin |
| 06T01DGH | others - hour hand |
Caliber 2P21
