printed the exterior from PLA and the interior from PA-GF because I wanted matte white and it was what I had on hand. PA-GF really shows a ridge pattern that's on the inner cylinder. the ball bearings at the specified size were a tight fit with this filament. they ended up wedged into the holes. they do a decent job keeping the cylindera together though so it's fine (even though the springs are not really doing anything) so -- works & looks great. my son is very happy with it.