The Mitre Square (parallelogram shape) has 45° faces on all sides and a flat base so that it can stand upright or be hooked on a lip. It has a 4-1/2" marking face. The Graduated Mitre Square is a combination tool with both 45° and 90° faces. The long face is graduated in inches - indicating the depth of the mitre rather than the length of the line. Sized 4" x 6-3/4". Again one face has a flat base so that it can stand upright or be hooked over the lip on an edge. We recommend that you buy the pair of squares to ensure full functionality and usefulness, as well as maximum value. Both are stainless steel.