These are a pair of brand new focusable extreme widefield high-eyepoint 30mm WF25X microscope eyepieces with 9 mm field of view. They are Achromatic (International DIN/JIS) standard size with outside diameter of 30 mm. They fit most common size microscopes including Leca, Zess, Nkon and Oympus. Give your microscope a boost with greater power & clarity at a fraction of cost. Features & Specifications: Focus Adjustable 25X Magnification Power 9 mm Super Wide Field of View 30 mm Mounting Size (in diameter) High Eye-point Design