Environmental friendly material- High quality modified polyethylene fiber filling material, the filter ball can be reused and can be cleaned by machine or by hand. Clean it regularly for better filtering effect. Easy and effective - Just pour on the machine, also suitable for your sand filter system. The filter balls are easy to use and can be used with any common sand filter system.comfortable. Design-Dense design, high water permeability, lighter, more efficient, excellent filtration performance, environmentally friendly and recyclable. They have a long lifespan. How to save energy. [Perimeter] - Emphasize the cleanliness and quality of the pool. Whether cleaning swimming pools, ponds or aquariums in the garden. Use filter balls to bring you water quality effects Clean and neat! Product Description Filter Ball Features: - Excellent filtering effect. - High pump efficiency. - Reusable, save money and energy. (clean and machine washable). - More grit. - Extends the life of the sand filter system. - Less backwashing and longer life. - Compatible with all sand filter systems! Material Specifications: Material: Polyethylene, recyclable. Diameter: 50mm. Appearance of the sphere: white, round. Lightweight and easy to use: 1. Open the filter container of the sand filtration system. 2. Remove existing filter material (if present in container) and clean filter container. 3. Fill the filter container with filter balls. 4. Close the filter container. 5. Turn on the machine and start working. Packing List: 1 Pack Pool Cleaning Balls. "Note: The data are all manual measurement, please allow 1 - 3cm error, due to the difference in light and display, there will be a certain color difference, depending the physical object received Delivery Quantity: (according to the main image)