Polypropylene hollow ball 1)Various colors and materials can available 2)Mainly used in water treatment 3)Good quality Shangyu Hongda Plastics ... ISO 9001 Quality System Certification, product quality, performance, safety and reliability. Product nameSpecificationMaterialApplicationSolid ball4mm-55mmPP,PE,ABS,POM,PA,PMMATrackball ... welcome to chat with me. Polypropylene Hollow Ball For Water Treatment