Focus Scale Loupe Power 15X Diopter 16D Focal Distance 0.8 in Lens Diameter 13.00 mm Features High Resolution Achromatic Color Corrected Lens Optional Light Source Comes Complete With Measuring Reticule Focusing From +2 To -2 Diopter With A Smooth Helicoid Focus Mechanism 360 Degrees Clear Acrylic Base Optional Reticules With White Markings Includes Protective Carrying Case Lens Cleaning Cloth