This is a pair of brand new eye-guards that fit all AmScope SW, SM and ZM series stereo microscopes. They also fit any eyepieces with 33 - 35mm O.D., including Nikon, Leica, Olympus and wild type stereomicrosocpe eyepieces. They are foldable for different applications. Features & Specifications : Eye-guards for 33-35mm O.D. Eyepieces Fitting AmScope SW, SM and ZM Series Stereo Microsocpes Fitting Nikon, Leica.