Burris Thermal Optics 57mm U.S.E. Smartclip Black. Options available are for 30-63.5mm objective lenses. Screw on the adapter to your Burris Thermal Clip-On and secure to your optic's objective lens using a quick-detach cam lever. Size is determined by the outside diameter of your optics objective bell. Specifications for Burris Thermal Optics 57mm U.S.E. Smartclip: Manufacturer: Burris Color: Black Finish: Matte Fabric/Material: Aluminum Diameter: 57 mm Size: 57mm Package Contents: Burris Thermal Optics 57mm U.S.E. Smartclip Burris Forever Warranty (Non-Thermal Optics) and Three Year Limited Warranty (Thermal Optics) All Burris Optics (with the exception of Thermal products) are covered by the Burris Forever Warranty . Burris Company Inc. ("Burris Co. or "we") warrants that its Burris Optics products (nonthermal optics products) will be free from manufacturing defects for the product's lifetime from the date of purchase or delivery (whichever occurs later). Burris Co. also warrants that its Burris Thermal Optics products will be free from manufacturing defects for a period of 3 years from the date of purchase or delivery (whichever occurs later) by the original purchaser. Warranty information and warranties are supplied solely by the manufacturer and not this retailer. This retailer publishes information from the manufacturer for information purposes only and the manufacturer is solely responsible and liable for any warranty information and warranties published by this retailer. Please reference the appropriate manufacturer documents or reach out to the manufacturer directly for full warranty terms and effective dates. Burris Thermal Optics 57mm U.S.E. Smartclip Black 626640