You can see the individual STL files and an AMF file. AMF is an open standard for 3D printing. In the AMF file, the shapes are already merged, you can open the multi-material file right away.They were merged in Cura as follows:- First configuring Cura to use two extruders in the Preferences menu. - Then Load the two objects.- Right click on one of them to select "Merge".- Print!If you want to can Save the model again. If you give it the extension .amf it will create the multi-material file for you!