Treated with Microban Antimicrobial Product Protection built into the sponge. Fights odor-causing bacteria, mold and mildew. Hydrophilic sponge. Fully threaded posts ensure maximum security of mop refills to mop head assembly. No loosening of thumb screws ? prevents sponge refills from falling off.Type H refill fits all Quickie 041 and 047 series mops. Scrubber strip included.