Thank you for viewing. Nikon FM Eyepiece Collection Diopter Correction +0.5 Comes with the original box. This is used to correct the diopter when the viewfinder is difficult to see due to farsightedness or wearing reading glasses. You screw it into the viewfinder. It is for the FM, but can also be used with the FM2, New FM2, and other models with the same viewfinder diameter. I think it's in good condition as it was only tried on a few times, but please understand that it has been stored at home for a long time. Thank you. #Nikon #Nikon #FM #FM2 #NewFM2 #Eyepiece #DiopterCorrection #Viewfinder #Accessories #Camera