Enjoy a sparkling clean pool by keeping your pool filter performing its best. Your pool filter is only as good as its filter, so trust the Summer Waves Type D Pool and Spa Replacement Filter Cartridges (4-Pack) to capture contaminants and debris in your water. These replacement filter cartridges filter out debris, dirt, and other contaminants thanks to ultra-thin, heavy-duty paper with more pleats than the average pool filter cartridge. This allows them to trap and hold onto fine dirt and sand. Each cartridge only needs to be replaced every two weeks, giving you time to enjoy a refreshing summer all season long. Easily change your filter cartridge every two weeks and relax in a debris-free pool. Make sure your pool is kept safe and clean all season long with the Summer Waves Type D Pool and Spa Replacement Filter Cartridge, now in a four-pack.