Beautiful design and durability built to last Quality optics with stunning HD clarity 100% quallity materials used and tested extensively Once the sight is installed on the Hi-Rise block, the entire assembly can be mounted on the weapon. First, loosen the mounting screw so that the clamp will fit over the tapered side of the firearms Picatinny or Weaver rail. Ensure that the tapered clamp on the riser is oriented with the chamfered (beveled) end of the clamp at the top. Ensure that the risers cross screw with nut is tightened to clamp it firmly to the weapons rail. Turn the large nut on the riser block ? to ? turn with a coin, screwdriver or ? wrench. WARNING! Do not over tighten.table.productattributes, .productattributes td { border-bottom: 1px solid #ddd; border-collapse: collapse; padding: 2px; text-align: left; }