The file 'Test Tube Rack – 12 ML Tubes 3D Printer Model' is (stl) file type, size is 154.9KB.
1x top
1x bottom
2x side
no raft or supports needed
just stick together, should fit firmly, if not adjust the gaps.
In my design, the parts are 4 mm thick and the gap is 5 mm (in theory). It fits well then.
bottom.stl | 489.7KB | |
side.stl | 2.2KB | |
top.stl | 546.0KB |