Every Nikon Monarch Rifle Scope is constructed from a 1-piece main body tube machined from aircraft grade aluminum for the utmost durability. The Monarch features Nikon's Ultra ClearCoat optical system that delivers 95% light transmission. Each Nikon Monarch has a fast focus eyepiece and hand turn windage and elevation knobs. Shockproof, waterproof and fogproof. 

Link to parts manufacturer