Sightron’s SII Big Sky line of rifle scopes have been designed and built to meet the demanding needs of both competitive shooters and hunters who shoot long range. These include a one-piece tube, ExacTrack adjustment system, and Zact-7 Climate Control Coatings. Each scope has target knobs and an adjustable objective lens. Eye relief is between 3.7 and 4 inches. Specifications: Magnification: 4-16X Objective Diameter (mm): 42 F.O.V. FT.