The byomic erecting eyepiece has a magnification of 1.5 x and is suitable for telescopes with a diameter of 31.8 millimeters (1.25 inch). telescopes and eyepieces turn the image upside down, but if you look at the stars, this is not a problem. by means of a erecting eyepiece you can put the image upright again, so that you can also use the telescope for observations on the land. you can also view birds or other objects with a telescope. you simply place the reversing prism into the eyepiece holder and place the eyepiece in the erecting eyepiece. Usage byomic erecting eyepiece 1,5x In addition to that the erecting eyepiece enlarge the image by 1.5x, it turns the image around so that your telescope is also suitable for making observations at country level in order to observe birds, for example.