Corrugated Board Construction linerboard and medium Material heavy paper---containerboard Facings---kraft linerboard Medium---one-ply sheet, hardwood or recycled fiber Linerboard flat facing Medium (fluted wavy)二. Corrugated Board ⚫ 1. Construction : linerboard and medium Material :heavy paper ---containerboard Facings---kraft linerboard Medium---one-ply sheet, hardwood or recycled fiber Linerboard (flat facing) Medium (fluted wavy)