When I received the filters, I immediately took them out of the box to inspect them. They had a slight yellowish kind of color, like they had been wet and then dried out. They were not the bright white color like the ones I purchase at the store. Because I was out of filters, I went ahead and put one in my humidifier. Filters usually last 30 days. I filled my humidifier with spring water and a few days after usage, the filter had turned completely yellow around the edges and had a smell, kind of like what you would smell on a used car filter. I tried another one, thinking maybe I just got a hold of a bad one. It did the same thing. I went to the store and bought my usual filter and compared the two. The store bought filter was white and had a clean smell to it...the Relion Humidifier Filter ordered thru Amazon had the oily/urine kind of smell. I will not buy these filters on line again. Was not pleased with the product at all!