What is the "pleat pack" and what does it do?

It functions much like a net that keeps out the contaminants - and it's a much bigger net than the old filter. This net basically keeps the contaminants from getting through the filter. One other unique aspect of the filter is that it emits a positive electrostatic charge which attracts the negatively-charged microbial and chemical impurities, acting much like a magnet to trap these contaminants in the filter media. This filter is also antimicrobial.