The "Tankin is CNC machined from solid steel to give it the weight necessary for no-hassle crosshair leveling. First, your rifle's action must be level. (you can use our Action level for that) Then to level the crosshair in your scope to the leveled action, place the "Tankin on top of your elevation turret with the scope ring caps loosely in place. Then rotate your scope until the bubble lines up between the lines in the tank and you are now plumb to the rifle. Finally, tighten the scope ring cap screws evenly until tight and you are ready to hit the range.