1. Prevent debris from entering the filter drum and extend the filter media usage time 2. Prevent young fish and shrimp from being sucked into the filter drum 3. Easy to use, directly into the water inlet basket 4. Suitable for most filter drums in the market including 250-600 CF600-1200 5. Product size: The length is about 7-8CM diameter is 4.5CM inner diameter is 22MM Length about 5-6CM diameter 3.5CM / inner diameter 15mm

http://olla.gr/10-pcs-special-protection-cotton-sleeve-for-aquarium-filter-suction-port-inside-diameter-22mm/