The Sharp FZK50HFU is a replacement True HEPA filter designed for Sharp s FPK50UW Air Purifier. Your air purifier is only as powerful and effective as the filter you put inside, and Sharp's replacement parts are essential for maintaining product performance. Each Sharp air purifier filter is designed specifically for a particular unit style. Not only will genuine replacement parts fit like a glove, but they also have the sleek and seamless design to match so that you can get the most out of your Sharp air purifier.