Comparison : Item # 40563, 2 x 0.625 x 0.25 x 12 Inch (in) Steel A36 Channel
Item # 40564, 2 x 0.625 x 0.25 x 24 Inch (in) Steel A36 Channel
Item # 40565, 2 x 0.625 x 0.25 x 36 Inch (in) Steel A36 Channel
Item # 40566, 2 x 0.625 x 0.25 x 48 Inch (in) Steel A36 Channel
Item # 40567, 2 x 0.625 x 0.25 x 72 Inch (in) Steel A36 Channel