The Feather Vision Vitri Lens is an excellent glass lens, developed in collaboration with Zeiss engineers. The advanced Verde Vitri™ design combines superior ZEISS supplied glass using specifically designed and proprietary curve structures, finished to the highest standards, and comes complete with one of the best ZEISS anti-reflective coatings on the planet. Utilizing complete in-house ZEISS processes ensures the highest quality product available.The specific coatings used for the Vitri lens are exceptionally durable, easy to clean, hydrophobic, oleophobic, anti-static, and boast a light transmission of 99.98%. This is an exceptional choice for the compound archer looking for high performance for all archery formats including low light, long distance, or higher powers. Specifications 1.75" fits most large 3D scopes such as Axcel AV41 and AX41, CR Apex 3D, Viper 3D, etc. 1.35" fits most small target scopes such as Axcel AV31 and AX31, CR Apex target, etc. Please contact us for custom sizes