Due to the volume of the sponges, we will squeeze it for better transportation. It will come back to its size after you put the sponge into water for a while. Please take care to place the order if you mind. Thanks very much for your kindly understanding.Features:Biochemical sponge filter provides biological filtration to the aquarium, helps to stable water quality.Increase the oxygen solubility.Working noiselessly, very durable, can be used for years.Good permeability, easy to clean.Perfect filters accessories for your tank and aquarium.The foam can be cut and is suitable for all kinds of fish tanks.Speicificaitons:Product name: Aquarium Sponge FilterColor: Black (Show as picture)Sponge Size: 50cmx50cmx2cm/50x12x2cm/40x30x2cm/40x30x3cmReminder:1. Soak the sponge in the aquarium water for 5 minutes before use, by doing this will help nitrifying bateria colonise easier.2. Always use aquarium water under room temperature to rinse clean the sponge, never use hot water.3. It must be used through connecting the air pump.Including:1pcs Aquarium Biochemical Sponge Filter