The Sightron S-TAC-4-20X50FFPZSIRMH Rifle Scope features a magnification of 4-20X with an objective diameter of 50mm and tube diameter of 30mm. The fast focus eyebell allows for quick and easy adjustments when in the field. The target turrent allows for .1 MRAD adjustments and is resettable to zero with protection by rugged windage and elevation caps. A pop up style zoom ring lever allows eas of use in cold weather climates. This scope features ExacTrac windage and elevation adjustment system and is waterproof, shockproof, and nitrogen gas charged.