This is a brand new EXTREME widefield higheyepoint 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 and Specifications10X Magnification Power; 22 mm Super Wide Field of View; 30 mm Mounting Size (in diameter); High Eyepoint Design;