The AmScope SW-3B13X-FRL binocular stereo microscope head has a pair of 10x20mm widefield high-eyepoint eyepieces, a 1x/3x objective, a 0.5x Barlow lens, and a single-arm boom stand. The microscope head has a 3" O-ring style mounting ring. The binocular viewing head has an interpupillary range of 47 to 75mm, a 45-degree inclination to reduce eye and neck strain, and 360-degree rotation to enable sharing. The WF10x20mm super-widefield high-eyepoint eyepieces combine with the 1x/3x objective to provide 5x, 10x, 15x, and 30xmagnification, and a longer working distance for inspecting large-scale specimens that require handling or repair. The microscope includes a 0.5x Barlow lens that can be added to the objective to decrease the magnification range. A Barlow lens with a magnification of less than 1.0 reduces magnification and increases the working distance. High-eyepoint eyepieces ease viewing for users who wear glasses, dioptric adjustment accommodates individual eye-strength differences, and eye guards ensure comfortable viewing. The optical glass lenses provide sharp images, and are fully-coated to ensure high-resolution images. A stereo microscope, sometimes called an inspection or dissection microscope, has low magnification and a long working distance that enables users to manipulate the object being inspected. The removable 8W fluorescent ring light provides cool, white light for observing specimens as they would appear in their natural environment. A ring light provides shadow-free illumination. It has a 2-3/8" inner diameter and uses a 110V power supply. The microscope has a 17" pillar that has an 8" vertical working distance. The 16" single-arm boom has a 24" overall length. Bilateral focus eases use for left- and right-handed users. The microscope head can be rotated on the X- and Y-axis. The solid cast-steel base is 1-3/4 x 9 x 9 inches (H x W x D, where H is height, the vertical distance from the lowest to highest point; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back). Specifications Head Binocular Magnification 5x, 10x, 15x, 30x Objective power 1x/3x Eyepieces (30mm) WH10x20mm Optical working distance Up to 4" Field of view 0.787" at 10x Microscope stand Single-arm boom stand Head movement X- and Y-axes Illumination type Episcopic (reflected) Light source Fluorescent ring, 8W Power 110V-120V Microscopes are instruments used to enhance the resolution of an object or image. Types include compound, stereo, or digital. Compound microscopes use a compound optical system with an objective lens and an eyepiece. Stereo microscopes show object depth in a three-dimensional image. Digital microscopes are used to display an image on a monitor, rather than looking through a lens. Microscopes can have monocular (one), binocular (two), or trinocular (three) eyepieces, with varying magnification abilities. Magnification ability refers to the size of an image. Resolution, also known as resolvant power, refers to the clarity of the image. The interaction between field of view (FOV), numerical aperture (NA), and working distance (WD) determines resolution. Microscopes can control magnification through a fixed focus, or through a range of adjustments. They can also utilize LED, fluorescent, and mirror light sources to help control viewing capabilities. Microscopes are widely used in education, lab research, biology, metallurgy, engineering, chemistry, manufacturing, and in the medical, forensic science, and veterinary industries. United Scope manufactures microscopy equipment and accessories under the brand name AmScope. The company, founded in 1996, is headquartered in Irvine, CA. What's in the Box? Binocular stereo zoom head with 1x/3x objective WH10x eyepieces, one pair 0.5x Barlow lens Single-arm boom stand with focus rack Fluorescent ring light, 8W (FRL8) Eye guards, one pair