High quality material: The filter sponges are made from the high quality filtration foam, BPA free and safe for your fish, without harming the pH quality of the water, good for freshwater and saltwater environments Practical Aquarium Accessory: Can be quickly and easily attached to the aquarium inlet tube stem, just cover directly over your filter water inlet. Prevent small fish or shrimp from being drawn into the filter Effective Filter Protection: Can help trap particles and debris and extend the life of your filter media, provide clean flow efficient water with less clogging for long lasting filtration Size: approx 8cm high, 4cm diameter, 20mm inner diameter Package Contents: 10 PCS x Aquarium Prefilter Sponge