Simplified spinal cord cross section 3D print model

I am new to CGtrader and this is the first model I have purchased. This is a nice simplified model of the spinal cord. I am printing a classroom set of this. They will be used in a HS anatomy class. The files are not ready to print in the sense that you first have to open one of the files in meshmixer or similar application. Then separate the shells and then export each shell as a stl file. It would have been nice if the creator had provided individual stl's for each piece of this model. I combined the two white matter shells and printed them as a single model using white PLA (with supports) then printed the gray matter separately using gray PLA. The gray matter slid inside the white matter with a bit of force. I haven't printed the vertebrate yet but expect that to fit around the white matter nicely. Now that I have figured out how to split a single STL file into individual shells, I would definitely purchase other models like this one.