The Nikon M2 is a 27.5mm extension tube for manual focus F-mount lenses. Though it was originally designed to provide 1:1 magnification on the original 55mm f3.5 Micro-Nikkor- and it still does!- it’ll fit any F mount lens. Worth noting: This tube does not preserve any automatic functions, including metering, so you’ll need to stop down manually to determine your exposure. Some cosmetic paint wear, good function.