Stretcher Strips are used to create the frame around which the cotton or linen canvas is stretched. Stretcher strips can be made from wood, metal, or a combination of the two. Cross braces are used to provide additional support to the frame, to keep it square, and to help prevent warping and twisting. Cross braces should be ordered in the same length as the stretcher bar to which they are parallel. Cross braces can either be installed in a ladder fashion, parallel to each other, or intersecting, in a crossing manner. In order to have the cross braces intersect or cross over each other, they must be ordered notched.