Cost effective choice Regular replacement of paper filter cartridges can be costly. These washable and reusable foam filters reduce ongoing pool maintenance costs by allowing repeated use. Size options S size Height: 7.3 cm (2.87 in) Bottom circle diameter: 10.8 cm (4.25 in) Middle hollow cylinder diameter: 4 cm (1.57 in) M size Height: 10.2 cm (4.01 in) Bottom circle diameter: 9 cm (3. .54 in) Middle hollow cylinder diameter: 3 cm (1.18 in) L size Height: 20 cm (7.87 in) Bottom circle diameter: 10 cm (3.93 in) Middle hollow cylinder diameter: 4 cm (1.57 in) density design The foam cover is attached to the filter inlet on one side. It traps fine debris and particles, improving filtration while maintaining water flow. Easy to connect to the filter and simple to remove for cleaning. Safety and environmental protection Protects small fish and shrimp from being sucked into the filter intake. Traps particles and debris, enhancing biological filtration and preventing tiny inhabitants from being drawn into the filter. Use scenarios Regular pool maintenance: disposable paper cartridges with these washable foam filters to lower ongoing costs. Seasonal maintenance: remove, rinse, and reinsert to restore filtration efficiency without long downtime. Aquatic life friendly filtration: use in pools or compatible ponds/tanks to reduce the risk of small fish or fry being drawn into the intake while keeping the water clean.