Anet A8 Extruder Button

This button is designed to have the screw in the top of the Extruder assembly pass right through it. Some other button designs just sit on top of the screw whereas the screw in this design holds the button down and keeps it all tight.

You will need to make sure you use the right length screw to get the right amount of thread to extend inside the extruder, this is necessary to hold the spring in place.