sump pit radon cover 2
https://myradonsystemfollowuptestguide.clearminster.com/posts/radon-system-follow-up-test-why-it-matters-after-mitigation-in-york-county
The sump pit radon cover sits firmly over that basement sump hole, blocking the soil gas that tries to seep through the gap. It's a simple, solid piece of plastic with a tight seal, often used in new construction or radon mitigation systems. When installed right, it keeps the air in your living space safer by cutting off one major entry point for radon.