Feature: 1. Premium Materials: It is made of high density foam sponge, which has better filtering effect and provides a safe environment for fish. A variety of sizes are available, and the versatility is stronger. 2. Enhanced Filtering: These pre filter sponges help trap particles and debris, extend the life of the filter media, provide efficient water flow, reduce clogging, and achieve long lasting filtration. 3. Long Lasting: It is suitable for use as a quicksand filter. Sponge body should be used to separate the internal medium (such as quartz sand, etc.) from the bottom acrylic sheet to extend the service life of the equipment. 4. Slim Design: Innovative ultra thin design saves the internal space of the aquarium and is more beautiful. Please check the usage of the sponge regularly, and replace it if it becomes thinner. 5. Wide Range Of Applications: Suitable for shrimp tanks, fighting fish tanks, breeding tanks, goldfish, discus, guppy, fry, juvenile fish or other fish. Safe for your fish, suitable for freshwater and saltwater environments. Specification: Item Type: Filter Sponge Material: Sponge Purpose: Fish Tank Filter Cotton. Package List: 1 x Filter Cotton