3D printed flow adapter made of PLA plastic These work great for adapting air flow where some leakage is acceptable Other applications may require extra treatment of the plastic to make airtight/watertight.  The light gray color makes a perfect base for painting any color you need.  The units you receive will not have any writing on them to indicate size. The thickness of this adapter is 33mm. We offer a custom adapter design package: https://www.ebay.com/itm/194650949382