KRAFT TOOL CO 6 Ft. x 1 In. x 4 In 1" Width x 4" Height X 72" Length Magnesium screed. Magnesium is 30% lighter than aluminum. Magnesium is also more rigid than aluminum! Made of high purity Magnesium screed will not rust or rot. Perfect tool for straightedging concrete without warping and waste using wood straightedges