export joist 1.light steel keel 2.the manufacturer 3.high quality 4.environmental aluminum keel light ... ,0.27mm,0.3mm,0.35mm,0.4mm6. The length, thickness and color can be provided in accordance with customers' ... mm)Main channel38x12mm0.7,0.8,0.9,1.00According to your requirements38x8mm0.5,0.6,0.8,0.9, ... .50Card light steel keel19x25mm0.619x28mmm0.8019x320.9019x38 1.0 the manufacturer's joist and keel