The Sightron SIII 10-50×60 riflescope features a 30mm main body tube with extra wall thickness for added ruggedness and durability. Oversized target knobs can be reset to zero and provide positive audible clicks and a side focus parallax knob. All SIII Scopes feature Sightron’s unique ExacTrack™ windage and elevation adjustment system. No other system on the market comes close to the precision and performance of ExacTrack™. The SIII Series feature large objectives with fully multi-coated precision ground glass with Sightron’s ZACT-7 Revcoat™ seven layer multi-coating throughout the entire lens system. These lenses provide some of the highest light transmission in the industry. A European style fast focus eyebell accompanies all SIII models. 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. They are waterproof, nitrogen filled and provide a lifetime of internal fog protection from inclement weather.