This is a plug for MFT style workbenches with 20mm holes.  I designed this one to be made with TPU.  I found that plugs made of harder material were eather too loose or too tight.  Even when they fit well, I did not like how they would scrape the inside of the holes.  With the TPU plug, I could make it fit tight enough that I didn't need to worry about sucking up with a vacuum and they were still easy to remove without wearing on the inside of the hole.  I printed these with 100% infill.