The new Riester e-scope? is the perfect blend of leading-edge LED technology, more efficient diagnosis and an environment-friendly energy source. Because the e-scope? breaks new ground with its world innovation, the IPC (Integrated Power Converter): younger, smarter and greener. With 2.7 V vacuum bulb for higher-contrast and more efficient diagnosis. Dioptre disc with 18 corrective lenses ( 1, 2, 3, 4, 6, 8, 10, 15, 20 dioptres). Easy-to-use aperture wheel with six different apertures (fixation star, large circle, small circle, red free filter, blue filter, semi circle). High performance optics with aspherical condenser lens. Spectacle protection. Parallel optical path and dust-protected.