Nikon 8415 4-16x50 Monarch X Riflescope (Mildot Reticle) (Black) Professional riflescope with unmatched durability, decision-making resolution and go-anywhere ruggedness 30mm one-piece main body tube constructed of aircraft grade aluminum; precision ground and polished Eco Glass lens Mildot reticle, 50mm objective diameter, 4x to 16x magnification, 3.5 inches of eye relief Nitrogen-filled and O-ring sealed for protection against water, shock, and fog; multi-coated optics Backed by Nikon's full lifetime warranty