The rectangular shaped magnifying lens "stretches" the traditional 5-inch circular viewing area to 6.75 inches. This wider viewing area under the lens allows for comfortable vision with both eyes and also reduces eyestrain and fatigue. Visual scanning speed is increased because more surface area is magnified. The 3-diopter lens is made of crown-optical glass and measures 6.75 inches by 4.25 inches. The 8MR-150 features a 26-inch adjustable arm while the 8MR-200 extends 40 inches. Proper magnification requires proper lighting to be effective. With proper illumination levels, magnification requirements are significantly reduced. That is why Dazor uses a powerful 18-watt compact fluorescent light source (included) to produce 130 footcandles at 15 inches above the work surface. Exact positioning of the light source behind the lens allows for a choice between even, shadow free illumination, or a hi-lighting effect. Shadow free viewing is achieved by holding the object directly under the light source. Equipped with 3-conductor cord. Available options include a Natural Light (3500 Degree K) bulb, a Cool White (4100 Degree K) bulb and a Protective Shield (8SD900-1).