Nikon 8413 2.5-10x44 Monarch X Riflescope (Mildot Reticle - Illuminated) (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 Illuminated mildot reticle, 50mm objective diameter, 2.5x to 10x 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