The key is used to depress the correct pattern on the keypad and can then be used to lock into the rail on the door knob cover, to turn and unlatch the door. The Doofer also has a protruding end that is useful for accessing other keypad doors, lift buttons... Any public use button!
This page allows you to download the 3D files for custom keys as well as the default key and knob covers.
To generate your own key type your code and hit submit (*hint - use digits on both sides and spread out - this is to give the key a better grip on the knob cover)
After previewing your key you can hit download to download the .STL file for printing.