Feature: 1. 45 DEGREE REFLECTION: This survey prism is designed for single side 45 degree reflection, with an effective diameter of 25.4mm, and a constant of +2mm. 2. OPTICAL GLASS: This prism uses optical glass, which enhances reflection ability, with full texture, clear and bright, making the measurement more accurate. 3. WIDE APPLICATION: Total station prism can be installed in tunnels, roads, bridges, dams, buildings or some other fixed places or objects to measure distortion and displacement. 4. STRONG COMPATIBILITY: This 45 degree prism is suitable for and other different types of total stations, widely compatible. 5. LONG LASTING: The total station prism is made of ABS material, which is sturdy and firm, not easily be damaged, ensuring long lasting use. Specification: Item Type: Survey Prism Material: Optical Glass, ABS Constant: +2mm Effective Diameter: Approx. 25.4mm/1in Use: Used for total station engineering tunnel surveying Package List: 1 x Survey Prism