Blast Off! cleans your filter two ways First from the inside – removing scale and build-up formed on the inside of the filtration material. At the same time, blasting water through the pleats to loosen and dislodge larger particles that have been trapped on the outside of the filter. Next, simply Blast Off! the outside of the filter to effortlessly rinse everything away. A perfectly clean filter from the inside out! Precision flow control lever prevents splashing and mess!