duplex board with gray back (grey back), various gsm, grade A, grade AB, grade B, in sheets, in rolls ... , 250, 300, 350, 400, 450, 500gsmIt is used for packaging and printing, mainly for cigarettes, medicines, health supplement, wines, facial tissue, shirts ... accessories, electric equipment, etc.we can also provide special gsm above 250gsm for both white back and grey back as customer's ...