National 431-420ALL-10 20x & 40x Dual-Magnification Stereo Microscope

BH #NA431420A10 • MFR #431-420ALL-10
National 431-420ALL-10 20x & 40x Dual-Magnification Stereo Microscope
Key Features
  • Dual 10x Eyepieces with Winged Eyecups
  • Angled Eyepieces with 360° Rotation
  • Dual 20x & 40x Magnifications
  • Achromatic Lens Configuration
The National Optical 431-420ALL-10 20x & 40x Dual-Magnification Stereo Microscope makes it easy and comfortable for groups of people to share the magnified view of large and small specimens through the eyepieces.
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National 431-420ALL-10 Overview

  • 1Description
  • 2Optical Performance
  • 3Use and Handling
  • 4Specimen Stage & Illumination

The National Optical 431-420ALL-10 20x & 40x Dual-Magnification Stereo Microscope makes it easy and comfortable for groups of people to share the magnified view of large and small specimens through the eyepieces.

Using a binocular head lets you view with both eyes open, which is not only more comfortable, but preserves true 3D stereoscopic vision with a rich depth of view. The two eyepieces are set a comfortable 45° angle, and the eyepiece head rotates a full 360° circle so people standing or sitting at a table or desk can all enjoy the view without having to have everyone move to the eyepieces. Optically the microscope is outfitted with two 10x power eyepieces that, when combined with the 2x and 4x objectives, provide 20x and 40x magnifications. The eyepieces are parfocal and parcentered, meaning they will require little or no focus adjustment when changing magnifications so views remain sharp and they remain centered when the interpupillary distance is adjusted—ensuring clear and crisp views for every user at both magnifications. These relatively low magnifications are ideal for larger objects like rocks and gems, textiles, models, circuit boards, and artwork. A diopter adjustment on the left eyepiece helps to compensate for individual eye strength and the eyepiece's interpupillary adjustment range makes it easy for all users to place their distance exactly where they need it. Finally, the eyepieces come with winged eyecups that block peripheral light; contrast and clarity are enhanced, especially in bright classroom or showroom settings.

The stage is integrated into the base to offer improved stability for larger specimens, and the viewing head can be raised an extra inch if additional clearance is needed for bulky specimens. Upper and lower LED illuminators light the stage and independent power control allows you to have just the upper LED on, just the lower, or both. Two stage plates are included: a frosted glass that passes light without the harsh glare, and a reversible white/black contrast plate that provides a stark difference between your specimen and background to enhance the view.

Optical Performance

  • Two 10x eyepieces produce 20x and 40x magnifications
  • Relatively low magnification range is ideal for larger specimens like rocks, gems, textiles, parchment, paper, stamps, and coins
  • Winged eyecups block peripheral light to improve contrast while helping to minimize distraction
  • Achromatic lens design virtually eliminates chromatic aberration, so colors are accurate and true to life
  • Single speed rack-and-pinion focusing mechanism brings the view into sharp detail, with a slip clutch to prevent damage due to obstruction such as getting too close to the specimen stage
  • Tension adjustment on the focus eliminates focus drift

Use and Handling

  • Binocular design makes it easier and more comfortable to use versus monocular heads, while also preserving a true 3D view and rich depth of field when viewing rocks or gems
  • Head set at a 45° angle to place user's head in a comfortable viewing position
  • Head rotates a full 360° to make it easier to share with a group or class
  • Wide 55-75mm interpupillary adjustment range accommodates a variety of users
  • Runs on 110-240VAC power; supplied with a 3-prong grounded US wall outlet plug

Specimen Stage & Illumination

  • Stage is integrated into the base to provide a wide area for larger specimens like circuit boards, rocks, parchment, fabric, etc.
  • Frosted glass stage plate transmits light without harsh glare
  • Reversible plastic black/white contrast plate enhances the view by providing a stark color difference between the specimen and the background
  • Blue filter for transmitted light
  • Locked-on stage clips hold specimen slides in place
  • Upper (direct) and lower (incidental) LED illuminators
  • Independent light control allows top or bottom illumination only, or both

National 431-420ALL-10 Specs

Microscope TypeStereo
Head45° Inclined, 360° Rotating Binocular
Diopter CorrectionYes
Nosepiece2-Position Nosepiece
Optical MagnificationNone
Objective2x, 4x
Illumination TypeTop: 1 x LED
Bottom: 1 x LED
Power SourceAC Adapter
AC Input Power110 to 240 VAC, 50 / 60 Hz
Interpupillary Adjustment55 to 75 mm / 2.2 to 3"
Dimensions13.5 x 9.5 x 6.7" / 34.3 x 24.2 x 17.1 cm
Weight9.3 lb / 4.2 kg

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