Product Description Features: Quickly and easily calibrate your scope outdoors, at the range, or at home. Easy to store and carry, ideal for long-range shooting, ensuring perfect level. Suitable for 20mm/11mm rails, quick and easy to mount on rails. Use this bubble level to ensure your rifle remains level when firing at targets. Quickly and easily mounts to the scope barrel. Specifications: Material: Aluminum Alloy Clamping Size: 20mm (0.79 inches) / 11mm (0.43 inches) Package Includes: 1 Scope Bubble Level Note: Please allow 1-2cm error due to manual measurement. Please ensure you do not mind before ordering. Due to differences in different monitors, the picture may not reflect the actual color. Note: 1. Please allow 1-3mm error and 1-3g weight error due to manual measurement. Please confirm you do not mind before ordering. 2. Due to differences in shooting light and monitors, the picture may not reflect the actual color of the product. Please confirm that you do not mind before placing an order, thank you! Regarding shipping: 1. Please ensure that your shipping address (e.g., name, street, house number, doorbell/email, etc.) is correct, otherwise the order cannot be delivered correctly. 2. All items will be shipped within 3 business days after the order is placed.