Thank you for a very cool way to organize my hex keys (allen wrenches)! I Printed mine multicolor (red and black - see image) with 2 shells and 15% infill. You need a bit of infill for the thick parts, but you don't need 2 shells. I'd recommend 1 shell and 15% infill. My pieces were difficult to asseble without some sanding and my hex keys don't fit in the holes (holes are too small). No biggie, I can drill them to size. But it would have probably been perfect if I'd used 1 shell instead of 2.