BML-1 Magnifying Bookmark Fresnel Lens keeps your page saved, and also works as a 2x Magnifying glass when needed for small text, also have a ruler for doing measurements, comes in protective storage sleeve.Ultra Slim & Lightweight Bookmark Magnifier with ruler in both metric and English scale and top tassel. It is a useful magnifying glass, page holder and bookmark, ruler. Ideal emergency magnifier and Survival Lens/fire starter for campers and preppers.