This is an anti-vibration mount for the Openpilot Copter Control multirotor control board. It should fit any square board with 30.5mm mounting hole spacing.
Note: The only way I was able to meet the bounding box minimum for this material was to sprue two of them together. They just weren't big enough otherwise.
Warning: I've not yet received my first order for this, so it hasn't been tested yet. I've decided to post it for purchase due to Shapeways only offering this material for certain through June 20th. Order and use at your own risk!