Bubble Level for 30mm Riflescope Tubes - Aplaygo Rifle Scope Bubble Level for Precision Shooting or Hunting Fits 1.1 inch / 30mm Tube 1. For 1.1 inch ( 30mm) riflescope tube 2. Matte Black Finish + Aluminum alloy material 3. Mounts quickly and easily to the riflescope tube 4. Makes it easy to maintain a perfect horizontal hold during extreme-range shooting 5. For the most precise shooting, use this bubble level on a 1.1 inch(30mm) Riflescope tube to vertically align the reticle crosshair.