Sightron Big Sky Scopes feature all-weather construction and Sightron's unique ExacTrack windage and elevation adjustment system. In addition, the Sightron SII Big Sky also features finger adjustable, resettable windage and elevation knobs. One advancement within the Sightron Big Sky collection is the ZACT-7 Revcat Multi-coating, which is a seven-layer multicoating with precision ground glass, which creates superior light transmission and resolution. Sightron is precision optical equipment for serious outdoorsmen. Receive FREE Ground Shipping on all orders over $39.99.