BL1 Vortex Optics Bubble Level 1 INCH Tube For the most precise long-range shooting, use the bubble level to ensure that the rifle is perfectly vertical. This will eliminate potential error caused by shooting a canted rifle. Mounts quickly and easily to the riflescope tube. Specifications: Weight 6.7 oz Outside Diameter (inches) 2.2 - 2.4 inches Outside Diameter (mm) 55 - 61 mm
