SummaryDifferent parts for multicopters - mm - motormounts arm-250-structured printable structured arm for 250-size racing quadrocopters, it is compatible with ZMR250 carbon frame, or NUCLEUS or other ZMR250-compatible parts. arm-250-structured4 - same, as previous, but for Emax MT2213 motors (Tyr001 request) other parts will be added InstructionsFile names: mm-xxxxx-yy.. - motor mounts for motor xxxx and arm, made from various profiles - d12 - tube with diameter 12mm, d16 - tube with diameter 16mm, 10x10 - square profile 10x10 mm. W All parts was printed from ABS with 0.2 or 0.25 layer height, 4 top and bottom solid layers,40% fill. They have near the same weight - from 19 to 20 gramm. arm-250-structured - arm, zmr250 frame compatible. It has internal structure, so, don't print support . Material - ABS. Weight - 15g. Best results - with ABS, 0.34mm extruder, slic3r-stable, 0.2mm per layer, 3 layers for top, bottom, and perimeter, 15% fill density. Weight - 12g.