... . Product nameSpecificationMaterialApplicationSolid ball1mm-60mmPP,PE,ABS,POM,PA,PMMATrackball,Ball valve,Bearing ball, Roll on ball,and so onHollow ball10mm-100mmPP ... .Product nameSpecificationMaterialApplicationSolid ball1mm-60mmPP,PE,ABS,POM,PA,PMMATrackball,Ball valve,Bearing ball, Roll on ball,and so onHollow ball10mm-100mmPP ... look forward to receiving your order! plastic ball roll in guide rail