My 3D print is a medical test tube rack. The slots for the tubes to rest in are designed for the widely used 13mm (diameter) tubes. The slots are 13mm wide so the tubes will not float out of them if it is printed and/or used in space. The most cost efficient and convenient material is ABS plastic. The entire build fits in the 6 in x 6 in x 6 in and has as much area removed from the exterior without compromising the functionality of the rack. It also is squared off to minimize rafting and lessen the print time and material consumption.