a microscope has two of these

A microscope typically has two eyepieces or oculars. These are the parts through which the viewer looks into the microscope to observe the magnified specimen. The eyepieces are usually located at the top of the microscope and are inserted into the eyepiece tube or head. Each eyepiece contains a lens that further magnifies the image produced by the objective lens. Microscopes commonly feature binocular eyepieces, which means there are two eyepieces side by side, allowing for a more comfortable and three-dimensional viewing experience.