Usage Tips: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: 1. Please allow 1-3 mm error due to manual measurement and 1-3g weight error make sure you don't mind before ordering. 2. Due to the lighting of the photos and the difference of monitors, the pictures may not reflect the actual color of the real item. Please make sure you don't mind before ordering, thank you!About Shipping: 1.please pay attention to your delivery address such as: name, street, house number, doorbell/email without name, etc. is correct, or the order will not be delivered correctly.2.All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances.3.During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 347 hoursHope you have a pleasant shopping experience!