Bubble Level for 25.4 mm Riflescope Tubes - Aplaygo Rifle Scope Bubble Level for Precision Shooting or Hunting Fits 1 inch / 25.4 mm Tube 1. For 1 inch ( 25.4mm) 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 inch(25.4mm) Riflescope tube to vertically align the reticle crosshair.