Features: 1. Made of polyester fiber cotton cloth and 100% polypropylene plastic ring which is eco-friendly, shock resistant and pressure resistant. 2. It provide excellent mechanical filtration, which helps reduce the amount of ammonia-producing organic matter in your aquarium by trapping debris. 3. Also prevents large and small object like sand and coral from damaging aquarium equipment. 4. Solid construction and heavy duty stitching make these socks strong and durable so they can be cleaned and reused numerous times. 5. Micron filter socks are an essential part to keeping aquarium water clear and clean. Specification: Condition:100% Brand New Material: Polypropylene+polyester fiber Color: As Pictures Shown Micron rating for chooses:150um Weight: Approx. 41g Package list: 1 * Filter Sock Note: 1. Please allow 0~1 inch error due to manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard. .