Duplex board withgrayback (grey back): grade A and grade B, 230, 250, 300, 350, 400, 450, 500gsm It is usedfor packaging and printing, mainlyfor cigarettes, medicines, health supplement, wines, facial tissue, shirts, cakes, toothpaste,tools, computer accessories, electric equipment, etc. we can also provide special gsm above 250gsm for both white back and grey back as customer's request.