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)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)