AmScope 20x-40x Super Widefield Stereo Binocular Microscope Head 20X and 40X two super widefield magnification settings Offering high quality super widefield stereo erect images Super widefield high-eyepoint WH10X/20 eyepieces with foldable rubber eye-guards 48mm (in diameter) female thread for adding Barlow lenses or lights Mounting Size: 3" (76mm) in diameter