Size：    8*4’, 7’*4’, 6’*4’, 7’*3’, 6’*3’, customized    

Grade B：    Slight discolor, small crack, No hole, No fibre    

Thickness：    0.15-1.0mm    

Grade A：    No discolor, No fibre, No hole, No splits    

Grade C：    Medium discolor, Slight pin, bean hole, Light fibre    

Grade D：    Discolor, splits, egg size holes no more than 3