... polish wooden frame 2,surface is cork board. 3,backside is corrugated board. 4,cork nails as a se Basic information ... information of goods:1,surface is A grade bulletin board;backside is corrugated board.2,woode frame,different color can be painted ... 500 workers, specially producing different kinds of mini blackboard,chalk board, whiteboard, writing & drawing boards and color clay for children. Our ...