Dr. Elsey is passionate about providing the very best products for your cats. A few months ago, in an effort to keep the dust content as low as possible, we switched to a different clay mixture for Respiratory Relief. The new clay is slightly darker than the clay we were using because it is mined in a different area. The color will not interfere with performance. However, after customer feedback, we have decided to go back to the original mixture. Anything with a date code after 20.11.20 will be the original clay and it will not have a sticker on it that states “new & improved particle size”.