###Cutaway view of a click pen mechanism
This model shows the three main mechanical parts of a retractable pen:
1. *Push button* (with ratchet)
2. *Follower* (spring-loaded by means of the ink cartridge)
3. *Cam*
The complete model of [the pen can be visualized here](https://skfb.ly/SRCn). The animated mechanism can be seen in this [cutaway view](https://skfb.ly/Tq9N) of a retractable pen.
![model 1](http://c.yamahata.fr/images/click_pen/click_pen_close-up_view_KeyShot.png)
![model 2](http://c.yamahata.fr/images/click_pen/click_pen_close-up_view_2_KeyShot.png)
*Close-up views of the click pen mechanism (PBR renderings performed with Keyshot 6.1).*