The Nikon DG-2 is a flip-up eyepiece magnifier used for precision focusing- great for macro or copy work. The DG-2 has 19mm threads, compatible with many Nikon film cameras like the FE and FM; cameras with 22mm or rectangular eyepieces are compatible with the addition of DK-7 or DK-22 adapters, respectively (sold separately). In excellent condition. Eyecup is not included.