3 part and two part functional buttons. It uses an MFD to create the face color and label of the button. you can edit the text of the label, the type of button mechanism, and also add your own functionality in the MFD's vizzy code.
The 3 part button features a piston for button pressing mechanism, and is also able to easily attach onto surfaces. you can set the 3 part button to either have Momentary (button goes down and up upon press) or Latching (button stays down or up depending on whether it is activated) button property.
The 2 part button is a more user friendly option for part count conscious users. It does not have the button pressing mechanism and, in my experience, it doesn't like to attach to surface attachments, but you can still click on it.
Be sure to save to subassemblies for use on your crafts!
Note: for some reason, the 3 part button doesn't work with other 3 part buttons in the same craft, due to buttons accidentally sending commands to the wrong button controller, does anyone know how to fix this? :/