I needed a simple drain stopper for the regular German kitchen sink. Cause all the ones I found won't fit, I designed my own version in Tinkercad.

Print in TPU :

• print up side down (as seen on the Tinkercad picture)
• 4 perimeters
• concentric top/bottom fill pattern
• no infill
• 0.2mm layer height
• no supports

I used 95A TPU which works very well for me.