There are 1 filter protectors and 1 sponges. These air inlet filter covers small fish and shrimp from being sucked into the filter and causing death. Size: The size of the filter protector film is 69x24mm, the inner diameter is 12mm. The size of the sponge is 60x35mm, andthe inner diameter is 10mm. The shrimp filter cover is easy to use and can be directly inserted into the hard water inlet pipe, protects shrimp and fish from being sucked into the filter. The shrimp filter is suitable for various external filters with an outer diameter of about 12 mm in the water inlet pipe. It can make your water inlet pipe cleaner, reduce dirt deposits in the water pipe and reduce attenuation. Ideal for tropical fish farms, koi ponds, wastewater systems, cooling towers and other commercial and industrial systems.