Welcome to our store! GLASS MATERIAL: The prism lens uses excellent K9 glass assembly, which not only ensures accurate positioning but also has high durability. PRISM CYLINDER: This prism uses a silver-plated cylinder, protecting a prism with a diameter of 62 mm, with an accuracy of less than 5 arc seconds. HIGH ACCURACY: The tilted target can be inverted and adjusted to an offset of 0, -30 mm, and the included sight improves accuracy. STANDARD SIZE: The circular prism lens has a standard size, is easy to install and maintain, and is equipped with a cover to provide good protection. WIDE APPLICATION: Widely used in subways, railways, tunnels, dams, steep slopes, mines, highways, and other detection, with strong functionality. Item Type: Prism Lens Material: k9 glass, ABS Effective diameter: Approx. 64 mm / 2.5 in Constant: 0 mm, -30 mm Application: Widely used for testing tunnels, subways, mines, highways, dams, steep slopes, etc., suitable for measuring instruments. 1 x Prism Lens 1 x Lid 1 x Storage Bag Customers are our top priority. If you find any problems with your product after receiving it, such as damage or incorrect quantity, please contact us immediately. We strive to provide you with the best after-sales service.