... different prepunched holes in one purlinHole Sizeφ8,φ10,φ12,φ14,φ16,φ18φ8,φ10,φ12,φ14,φ16,φ1810*20,12*20 ... is free of maintenance. 6-10 times longer service lifeMaximum column sapcing up to 16m, at leat 5%-8% average cost cheaper than ordinary ...