Dandelion 1X 30 Red Green Dot Sight Scope Weaver Picatinny Mount Illuminated Crossbow Rifle Shotgun WARNING : All discharging of firearms should be done at an approved range or equally safe area , use of eye and protection is recommended. 38mm Tube with Best in Class Emerald Lens Coating for Maximum Brightness and Clarity, Clear and Sharp 4.0 MOA Dot ; Consistent and Precise Coin-adjustable W/E Knobs with 1/2 MOA per Click Increments "ZEROING" : Activate the illuminated reticle by turning the rheostat knob clockwise to brighten and counter-clockwise to dim. The lower numbers represent dimmer settings and the higher numbers represent brighter settings of illumination . The "0" position indicates that the unit is off. Each click of adjustment changes bullet strike at a shooting distance of 100 yards by the amount indicated on the windage and elevation screw dial plates to calculate the click value at distances other than 100 yards , use the fllowing formula: divide the distance (number of yards ) by 100 . THe resulting number, when multiplied by the click value stated on the windage and elevation dial plates will yield the actual click value of the scope the shooting distance. Distance / 100= N N*stated click value = actual click value