Introducing the AUS(TM) OFFSET bubble level Anti-cant device(R). Designed as part of our AUS Mount System as a way to keep the scope aligned and prevent the rifle from tilting to the side. This level is reversible to be used on the left or right side of the AUS Mount via the 4 mounting locations integrated in the AUS Mount body. Note: The AUS(TM) OFFSET bubble level was designed specifically around the Vortex(R) Optics Razor(R) HD Gen III 1-10x24 LVPO. Some larger windage knob optics may occlude the view of the offset. Like all Reptilia products, the Offset bubble level is 100% made in the USA and carries a full lifetime warranty against manufacturer defects.