Comes in wooden case for safety and elegance An ideal combination of field and magnification Sterilizable, Perfect equilibrium of magnification and field of view. Perfectly corrected for field curvature, astigmatism, aberrations and coma. 20D Double Aspheric Ophthalmic Diagnostic Lens Image Mag.2.97X, Aperture 48mm,Working Distance 47mm 90D Double Aspheric Ophthalmic Diagnostic Lens Magnification 0.64 X, Working distance 8 mm. Purpose- View the posterior pole using a slit lamp 78D Double Aspheric Ophthalmic Diagnostic Lens Magnification 0.77X, Working distance 10mm. Good all-around lens. Ideal option if the practitioner uses a single lens.