About a month ago I received a 17mm Nagler type 4 for my birthday. The person that gave me this eyepiece did not realize that I already had one. This eyepiece has never been put into a telescope before or ever been opened. It is absolutely brand new! I am asking $320 for the eyepiece. Thanks for taking a look at the ad. If there are any questions at all please feel free to e-mail me and I will get back to you as soon as possible.