The Rhin-O-Tuff HD4470 comb opener will open comb elements from ¼ inch, 6mm to 1.8 inch, 28mm. The HD4470 can open up to 21 element combs for documents up to 14 inches long. Will bind up to 1.18 inches (28mm) thick and 14 inches (356mm) wide. The opener has an adjustable ring opener control for repeatable comb opening positions. ★★★★★