The file 'Callisto Class (TOS) 3D Printer Model' is (stl) file type, size is 27.3MB.
Here is my kit bash based of the Callisto class starship (https://fasaststcs.com/index.php/thefleets/united-federation-of-planets/star-fleet/callisto-class-viii-frigate/), using Captain Mojo's Parts Kits.
It's scaled to 1/3788 but it should be easy enough to re-scale in the slicer of your choice.
I made it in OrcaSlicer.
Callisto_Class.stl | 62.0MB |