Perfectly align your scope and prevent cant error for maximum long-range accuracy. This anti-cant indicator ensures you are holding your rifle perfectly level for repeatable, range like precision. It’s also vital for proper turret adjustments and getting the right hold over with bullet-drop-compensating scopes. Made of precision-machined, anodized aluminum for long-lasting durability. Easily attach to your scope for convenient visibility while in the shooting position. Folds when not in use. Available: 30mm, 1".