Tha Walther Photo Corners are a must for traditional photograph albums as they are self adhesive and fit over the corners of the photograph. The front of the corner is clear, so doesn't detract from the photograph and the back is white, which is hidden behind the photo once it has been mounted. The measurement along the base of the triangle is 18mm and the length of the actual corner 10mm. The Walther Photo Corners give a retro feel to albums and make quite a statement. Also available in boxes of 1000.