DIMENSION: approx. 8.5x5cm/3.4x2 inch cylinder, the inside hole diamenter is 2.1cm/0.8 inch,please note these foam are pre filter sponges,so only have single hole.
ENHANCE BIOLOGICAL FILTRATION: these pre-filter sponges could help to trap particles and debris,and prolong the life of your filter media,provide efficient water flow with less clogging for long lasting filtration.
A MUST HAVE ACCESSORIES FOR FISH TANK FILTER: premium pre-filter foam sponges can be quickly and easily attached to the fish tank intake tube stem, preventing small, baby, or weaker inhabitants from being drawn into the filter.
A SECURATY FOR YOUR FISH HABITATE: give your fish pet a securaty habitate! these cylinder pre-filter sponge suit for all shrimp tank owners and anyone else who has baby or small fish in their tank,provide them a safe environment.
HIGH QUALITY MATERIAL: these sponges are made from the top-quality filtration foam,BPA free and safe to your fish,no harm to water PH quality, good for freshwater and saltwater environments.