Features: Quickly and easily level your optics in the outdoor, at ranges, or at home.Convenient storage and transport, Great for long ranges shootings, perfect level.Suitable for 20mm/11mm leads rail, can installed quickly and easily for rail.Use this bubble level to make surely your rifles level shootings the targets.Mounts quickly and easily to the rifles scope tube.Specifications: Materials: Aluminum alloysClamping Size: 20mm(0.79inch)/11mm(0.43inch)Package Includes: 1pc Scope Bubble Levelnote: Please allow 1-2cm errors due to manual measurement, make surely that you not mind before order. Due to difference between different monitors, the picture may not reflect the actual color.Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.