I got sick of buying new storage boxes for my laboratory for microfuge tubes. When I realized we had a million unused pipette tip boxes, I came up with the idea of using them for tube storage boxes. This insert will allow you to convert old pipette tip boxes into microtube storage holders for 20x0.5 ml and 20x1.5 ml tubes. The insert takes about an hour to print on my Flashforge Finder with no supports since it is completely flat.It's 2.5 mm thick with 15% infill-- that seemed to work fine to make it sturdy enough and print pretty quickly.