You can print as many frame elements to adjust the height. A band is for securing a piece of fabric in between the layers - it’s printed with flexible filament. To make it tight on the bottom piece, print it smaller, at 97%. For the stackable frames, print it at 100% (97% also fits, but it’s tight).

I’ve printed the whole thing in BASF recycled PET (rPET) apart from the band that was printed in Polymaker PolyFlex TPU-95.

layer height 0.2 mm, 3 perimeters. 15% infill