Dimension: Length 1.65", Width 0.78", Height 1.65". Inside Diameter 25.4Mm.Material: Machined From Aircraft Aluminum Alloy With Heavy Duty Steel Lock Plate For Maximum Hold.Protection Design: High Quality Synthetic Protective Strip On The Inner Surface Of The Rings To Protect Your Equipment.Application: Suitable For 11Mm Dovetail Rail Mounts.Easy To Install: Twist Lock Design For Easy, Fast And User-Friendly Installation. 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 24 hours Hope you have a pleasant shopping experience!