The Dennerle Nano corner filter accessory set contains everything you need to maintain the Nano corner filter and Nano corner filter XL internal filters: 2 foam blocks for the corner part (protective sponge), 1 straight connection piece (for extension or as replacement), 1 90° angle piece (for extension or as replacement), 1 air outlet pipe including end cap (for extension or as replacement), 1 cleaning rod for the air outlet pipe, and 1 cleaning brush for air outlet openings. It features a large surface area for filter bacteria, excellent filter performance, and ensures crystal clear, healthy water with a 3-layer special fleece for efficient filtration.