Vertex Power Range +25diopterto-25dioper Step 　 0.125D Prismatic Power Range 5 prism diopter Step 1 diopter Cylindnical Axis Range 0 to 180 degrees Step 1 degrees Lenses Accommodated Diameter 20mm to 100mm Eyepiece Focusing -5D to +5D Bulb 220V/110V/3W DC 3V Internal Reading Type