I purchased these plugs because I noticed that some of mine were missing. I live in the South and have the house treated yearly for Formosans. They new plugs arrived quickly but I was disappointed to discover they are made of hard plastic instead of rubber as I had assumed. Therefore, they do not provide a snug fit. Moisture can still get in and they pop out easily (probably why the originals went missing in the first place). Not all of the holes are exactly the same size either. (I actually purchased two sizes.) A few holes are between the 3/8 and 1/2 inch sizes, and were they made of a flexible material, the larger plugs would have fit.