... mainly used to make high strength chemical fiber tubes, yarn bobbins, industrial paper tubes for paper mill and plastic film ... following:1. Substance: 230g/m2-600 g/m22.Grade: B,F200,F300,F400,F500,F600,F700,F800,F1000 ... : Wrapped with vinyl film for waterproof, then core paper packed.If you have any interest in our product and ... to send me your inquiry at any time. high grade core board for paper core