Metal clip screw insert question

[Dan-the-man]

I just cant seem to make up my mind on what will be my next Spyderco! I just discovered the Calypso Lightweight, and wow i like it a lot. My question is how are the metal inserts stuck into the handle so they dont just slide out? Are they larger on the back side(do they have a head) , or do they have teeth that dig into the zytel?

This is really hard for me to explain, but i hope someone out there knows what the heck im talking about. Thanks!
Dan