... duplex paper,duplex paperboard, grey back duplex paper) duplex paperboard(duplex paper, duplex paperboard, grey back duplex paper)We can produce 230gsm, 250gsm,300gsm,350gsm,400gsm, 450gsm and 500gsmpaperboard with grey back or with white ... manufacturing and sales of paper products including photographing, designing, printing, paper carton, corrugated board, paper bag, paper box, gift box, ...