These 50x50mm hollow section aluminium rafters are designed to have the EconoGlaze Bar attached to the top of each rafter. This offers a stronger Glazing system and a much cleaner look than having timber rafters. Please check the EconoGlaze Span chart to find out which size is required. 4050mm and 6050mm lengths. Square corners (no radius), supplied mill finish or powdercoated.