The S3 SS10-50×60 Rifle Scope by Sightronfeatures a 30mm one-piece main-tube made from high quality aircraft aluminum. Tube thickness is more than twice as thick as one-inch models to provide maximum rigidity. This rifle scope features the ultimate in all weather construction. The rifle scopes are waterproof, nitrogen filled and provide a lifetime of internal fog protection for inclement weather. A European style fast focus eyeball accompanies all Sightron SIII SS Long Range Riflescopes. A quick turn of the eyebell allows the user to focus in a matter of seconds. Tweaking the eye focus is just a small adjustment away. The Sightron S-3 SS 10x-50x 60mm Side Focus Riflescope also features Sightron ‘s unique ExacTrack windage and elevation adjustment system. No other system on the market comes close to the precision and performance of ExacTrack. Large oversize target knobs with 1/8 inch adjustments are standard on all models. All Sightron Riflescopes feature target knobs that are re-settable to zero. All target knobs are protected by large heavy windage and elevation caps. A Side Parallax focus is available on all Sightron SIII SS LR Riflescopes. Designed for ease of use in prone and bench shooting the side focus will focus from 10-40 yards to infinity depending on the specific model. All Sightron SIII LR Series Riflescopes also feature ZACT-7 seven layer multi-coating with precision ground glass. These lenses provide superior light transmission and resolution for the ultimate in performance. Lastly, the Sightron S-3 SS 10-50x60mm Side Focus Rifle Scope is backed by Sightron’s Limited Lifetime Warranty.