Compatible with a wide variety of their fieldscopes, the Opticron 40862 HDF T Zoom Eyepiece features a long 22-17mm eye relief and a twist-up eyecup to make long-duration observation sessions comfortable and easy without eye strain, whether or not the user is wearing eyewear. Fully multi-coated optics complement those used on the fieldscopes to maximize light transmission and improve color, clarity, and contrast. While the magnification it yields depends on the scope it is used with, it will always produce a wide zoom range that allows for low-power wide fields of view with the ability to increase the magnification to make detailed observations. Opticron etched indicators on the body to help guide you along the zoom range for repeatability and ease-of-use.