Spacers for Zmr250 racing drone

These are spacers with which you can build lower version of Zmr250 racing drone. With these spacers used and 3mm arms distance between lower and upper plate is 22mm. Enough to fit PDB and FC.

Complete set of parts for Zmr250:
http://www.thingiverse.com/thing:1736627
http://www.thingiverse.com/thing:1736621
http://www.thingiverse.com/thing:1736423
http://www.thingiverse.com/thing:1717323