NightForce ATACR 4-20x50mm ZeroStop Rifle Scope 34mm Tube First Focal Plane Hourus TREMOR3 Illuminated Reticle Black. Equally at home atop a bolt action or a semi-automatic rifle the 4-20x50 F1 is smaller and lighter than the 5-25x56 F1 while offering a 25percent improvement in magnification over the 4-16x42 F1. With Digillum a ZeroStop turret power throw lever ED lenses and 20x max magnification the ATACR 4-20x50 F1 is our apex mid-power scope. Specifications for NightForce ATACR 4-20x50mm ZeroStop Rifle Scope 34mm Tube First Focal Plane: Manufacturer: NightForce Objective Lens Diameter: 50 mm Magnification: 4 - 20 x Tube Diameter: 34 mm Reticle Focal Plane: First Focal Plane (FFP) Exit Pupil: 2.5 - 8.3 mm Illumination Color: Red Finish: Matte Field of View Linear: 6.1 - 23.6 ft at 100 yds Eye Relief: 3.5 in Color: Black Weight: 35.2 oz Length: 13.9 in Parallax: 11 yds to infinity Illumination Type: Digillum Battery Type: Stand Alone Lithium Magnification Type: Variable Condition: New W/E Travel at 100 Yds: 100 - 130 MOA Package Contents: NightForce ATACR 4-20x50mm ZeroStop Rifle Scope 34mm Tube First Focal Plane NightForce C637: ATACR 4-20x50mm ZeroStop Rifle Scope 34mm Tube First Focal Plane Hourus TREMOR3 Illuminated Reticle Black