Katadyn Vario Ceramic Disc Blocks larger particles Field cleanable Genuine OEM Product Prevent clogging Increase the life of the filtration system Replacement Ceramic prefilter for the Katadyn Vario Ceramic prefilter assembly can be turned on to increase primary filter longevity, off to maximize water flow Ceramic prefilter assembly can be turned on to increase primary filter longevity, off to maximize water flow