The 6-diopter lenspiece gives a magnification of approximately 1.5X at a nominal working distance of 6 inches (150 mm), with a useful field of view of appprox. 2-3/4" x 3" (72 mm x 75 mm). The lenspieces are easily interchangeable in either frame. The one-piece optical element of the Model L loupe is designed with a fixed binocular angle, optimized for the power of the lenses; the lines of sight from each eye converge at an ideal working distance to provide low-fatigue 3-dimensional stereo viewing. Zeiss hands-free vision magnifiers are essential tools needed when engraving, when doing intricate embroidery and during extensive thorough inspections; in summary, Zeiss hands-free vision magnifiers are perfect for any precision craft involving long periods of viewing fine detail. These instruments bring together the industry's widest range of flexible, comfortable visor-mounts with the unsurpassed quality of Zeiss lenses.