CS-10 Select White Sand is the diffusing agent in natural gas Vented burner systems, it goes on top of the burner, beneath the embers. The gas spreads out as it passes through the sand, and illuminates the embers on it’s way to making a rich flame. This premium sand contains significantly less dust, and fewer impurities that can cause caking, and negatively impact your fire. The CS-10 is the perfect amount to cover burner systems up to 24″ wide. You will need more than one bag for systems larger than 24″. **Sand color may change with use, as carbon from the burn accumulates in the sand.