Aluminum alloy; length is5 in; width is 2.50 in; item consists of 1 tube support channel, p/n 9318145; 1 sheet .125 thk x 4.50 in l x 1.63 in w, which contains 2 holes .43 in. X .72 in, 3.00 in. From center hole to center hole, p/n 9290589-2; 1 sheet .125 thk, p/n 9290589-3