The Brunton Eterna 6.5-20x50 BDC Reticle Riflescope with Fast Focus Eyepiece has fully coated optics that provide a perfect image at any distance. This riflescope lets you use a multiple aiming areas for improved flight and precision at longer ranges. The Brunton Eterna 6.5-20x50 BDC Reticle Riflescope has a bullet drop compensating glass-etched reticle that grants you enhanced zeroing in on the point of impact at one distance. This Riflescope is waterproof and filled with Nitrogen, allowing the Brunton BDC Reticle Eterna Riflescope to also be fog proof, so you can take it practically anywhere. It has a fast focus eyepiece that lets you adjust the focus on your Hunting Scope quickly and without hassle.