Review on 🆒 Ergonomic Flush Type CAPLUGS - Pack with Improved Diameter by Chris Bowden

Plugs are made of very stretchy rubber or very rubbery plastic; they are quite hard if they are rubber, or rather soft if they are plastic. It's a fairly thin material that doesn't want to stretch/pucker too much and warp when you do. You have to push it a good bit before it touches the "inside" part of the hole. It sticks quite firmly, which is nice, but if you want to take it off, at least it can wrinkle nasty when you pull it out. This seems to work well as long as the surface around the hole is flat and smooth, but I haven't been able to test its sealing properties because the diameter of the 'plug' is too large. It's somewhere around 34-35mm. Otherwise it went in flawlessly and hooked into the 25mm hole.