Here is a listing for a Nikon DK-20C -2.0D eyepiece correction lens, which is difficult to find. The "D" in -2.0D stands for diopter. A diopter (symbol: Dptr, D) is a unit of refractive power (focal power) of a lens, mainly for eyeglasses. The glass surface is clean with no scratches or clouding, and is very beautiful. It is in near-new condition. This is the -2.0D, which is the most sought after by those with nearsightedness. This diopter rarely appears. As it is a Nikon product, the officially compatible models are: D300 series, D200, D100, D7000, D90, D80, D70 series, D5100, D5000, D3100, D3000, D60, D50, D40 series, F80, U2, U, US, F70D, F60D, F50D, Pronea 600i, Pronea S, FE10, and FM10. However, this adapter can also be attached to cameras from other companies. It can be used on Olympus OM1, Pentax, Canon, and other cameras! However, please install it at your own risk. Especially the popular -2.0D. The glass surface has a beautiful coating and no scratches, so you can still use it comfortably. This is a long-term product that will not appear often in the future. Not only for Nikon fans, but also for Olympus, Canon, Leica, and Hasselblad fans, how about it?