This eyepiece is used to focus objects for astrophotography. It has the focusing Bars type screen mounted on a brass threaded insert, rubber eyecup and endcaps and is in very good condition. I dont think I have a need for it and honestly do not know how to use it. It was aquired with a previous purchase, so if you are interested in it or are able to tell me how to use it, or know what it is worth, then please email me. It does not have the original box or instructions.
thanks Nick B