This is a design for an Altimeter clock. There are 2 versions available, each with it's own STL if needed, however it's suggested to use the 3mf file and change the settings for your printer. 

Single Extruder version - 23cm clock:
The faceplate and the back are to be printed as 2 separate pieces. For the faceplate, set the layer height to 0.2mm and from the Prepare tab, do a filament change at layer 18 (or 3 layers from the top). This'll help you achieve the white writing on top of the black.

MMU Version - 22.2cm clock:
Print face-down. Ensure that the bed is clean, level and monitor the first layer closely. 

Clock Mechanism:
Purchase a clock mechanism with atleast 7mm worth of threaded section. Ensure it comes with hands as the model doesn't include clock hands.

For private use only.

Hope you enjoy!