Athlon Argos HMR 4-20x 50mm Rifle Scope - BDC 600A SFP IR - The Argos HMR is a compact and versatile hunting scope featuring SFP, Side Parallax, Advanced Fully Multi-coated, Capped Elevation & Windage Turrets, Illuminated Reticle options. Advanced Fully Multi-Coated: Athlon advanced fully multicoated glass gives you better light transmission with optimum brightness and true color across the entire light spectrum.; Argon Purged: High grade Argon gas has a low thermal conductivity compared to nitrogen gas, resulting in better fog proof capabilities.; Waterproof: Regardless of how heavy the rain is coming down or an accidental drop in the water, this sealed and gas-purged optic will remain waterproof.; Aircraft Grade Aluminum Tube; Illuminated Reticle; Etched Glass Reticle; Fog Proof; Shockproof; One Piece Tube Construction