Radon test kits are devices used to measure the concentration of radon gas in indoor spaces. Radon is a radioactive gas that can seep into buildings from the ground, and prolonged exposure to elevated levels may pose health risks. These test kits typically include instructions and tools to collect air samples, which are then sent to a laboratory for analysis. The results help homeowners and businesses assess radon levels in their premises and take necessary steps to mitigate potential health hazards.