High quality - The aquarium filter is high quality stainless steel and is firm and durable. Protect shrimps and fish - The aquariats covered by the filter are small, avoid sucgesting small shrimps and fish. Anti-clogging - Prevents large crumbs from being sucked into the filtering system and blocked. Easy cleaning - When you need to clean, simply use your hand or brush (for example, a toothbrush), all dust accumulated on the filter protector. Multi-function - is ideal for tropical fish farms, koi ponds, wastewater treatment systems, cooling towers and other business and industrial systems. Circular internal diameter 15.5-16.5 mm (elastic) 3 cm diameter 8.8 cm height Note: Manual measurement error, please understand. Number: 2