Designed to accommodate large and small specimens, the National Optical 431-430PLL-10 20x & 40x Dual=Magnification Stereo Microscope makes it easy and comfortable for groups of people to share the view 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. These relatively low magnifications are ideal for larger objects like rocks and gems, textiles, models, circuit boards, and artwork. 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. 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 viewing head can be raised and lowered relative to the base for viewing flat or chunky specimens, with a maximum specimen height of 2.8" (7.2cm) and a working distance of 3.7" (9.4cm). The stage is integrated into the base to make viewing larger specimens like rocks, gems, textiles, and circuit boards easier. 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. The upper LED also has its own rheostat dimmer to provide the right amount of light. The LEDs emit very low heat versus conventional incandescent bulbs, which will prolong the life of live material so you can have more time observing them in their living state. 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.