DR-3 Rectangular Dome Magnifier with 2 flat sides for easy handling and more focused viewing area. This unique design takes advantage of naturally illuminating design of a bright field magnifier with the optical superiority of a thick aspheric lens, the plano base is raised .5mm to avert surface scratching. Its rectangular shape makes it easier to hold and guide along a reading path, the horizontal field of view is as wide as our Best Selling DM-3 Dome Magnifier.