Comparison : Item # 40,563, Steel A36 Channel 2x0.625x0.25x12"
Item # 40,564, Steel A36 Channel 2x0.625x0.25x24"
Item # 40,565, Steel A36 Channel 2x0.625x0.25x36"
Item # 40,566, Steel A36 Channel 2x0.625x0.25x48"
Item # 40,567, Steel A36 Channel 2x0.625x0.25x72"