This is a brand new EXTREME widefield high-eyepoint 30mm WF10X microscope eyepieces with 22 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. Features & Specifications: 10X Magnification Power 22 mm Super Wide Field of View 30 mm Mounting Size (in diameter) High Eye-point Design