Not sure where my key was lost, but I made this to allow me to change settings on my Hakko FX-951 soldering Station. It will probably work on other Hakko soldering stations that use this same key. When printing this use 100% infill, since any light leakage through the key will not interrupt the optical sensor there by not unlocking the change temp settings. I would also recommend a dark filament to print this with.
The author hasn't provided the model origin yet.