For those times you need help reading the printed page, the Magna-Rule ® from Bausch & Lomb doubles the height of letters. It lies flat on the page & magnifies two lines of type at a time without any need to focus. The 10" overall length offers an 8" scale in both inches & centimeters, making it very useful with tabulated data. The Magna-Rule ® also serves as a linear guide, so there's no need to squint & struggle. Magnifier Type: Ruler; Lens Magnification: 2X; Lens Width: 10"; Lens Height: 1/2".