... pricerite,good quality 1.Metal structure and the materials all in line with the national standards CB/ and T5237-93 standards ;Aluminum ... by automatic bending machine ,so each bends are consistent and in line with the national level standard ,flat , non-wrinking, non-deformation ... is using the High-quality and High-density Sponge, Durable and The same type, density is 35, Softness and hardness can be ...