The Original Radon Dome -SMR114-VWe think this is the best sump lid on the market. Eliminate a major radon entry point with this high quality durable sump lid cover. If your radon levels are high this lid provides an opening especially designed for an Active Sub Slab Depressurization radon mitigation system without having to core a hole in your slab. You are also able access the sump pit and pump without having to remove or adjust the radon mitigation piping after the installation.