... and strong enough,less flexible,high stiffness and quality Grey Paper Board specification 1.Weight:220gsm--1650gsm(1700g or more can be ... product is over than 0.35mm. 4.useage:Duplex grey paper board can be used to make gift boxes, cosmetic boxes, wine ... . high-end paperboard also can be used to make notebook paper, the cover of hardcover books, folders and albums, etc.5 ...