UTG 3-9X40 1" Hunter Scope, AO, 36-color Mil-dot, w/ Rings Emerald Lens Coatings, Built on True Strength Platform, Completely Sealed and Nitrogen Filled, Shockproof, Fogproof and Rainproof Premium Zero Locking and Zero Resetting Target Turrets with Most Consistent and Precise 1/4 MOA per Click Windage/Elevation Adjustment Mil-dot Range Estimating Reticle for Most Optimal Aiming and Shooting Performance, Parallax Adjustable from 5 Yds. to Infinity Innovative EZ-TAP Illumination Enhancing (IE) System with RGB in Dual-Color Mode and 36 Colors in Multi-Color Mode Complete with Picatinny/Weaver Rings and High Quality Flip-open Lens Caps Kindly refer the user manual attached below for troubleshooting steps and instructions.The installation instructions begin on page 8.