Item Type: Total Station Prism_x000D_ Material: Optical glass, ABS. _x000D_ Constant: Approx. + 2mm / 0.08in_x000D_ Effective Diameter: Approx. 25.4mm / 1in_x000D_ Use: Install on total station for engineering and tunnel measurement. 1Good Reflection: The optical glass ensures high accuracy in the measurement, which will also improve the clearness and reflection of the prism. 2Wide in Utility: Having been installed on total station, the mini prism can be used for the testing of tunnel, engineering, mine, dam, road an so on. 3Standard Design: Comes with 25.4mm effective diameter, the total station mini prism also has + 2mm constant for reliable working performance. 4Great Materials: Consisting of premium optical glass and ABS materials, the survey prism tool is not likely to break, very durable for long use. 5Easy to Install: Light in weight and compact in size as well, the 45 degree prism accessory is very convenient to install within several minutes.1 x_x000D_ _x000D_ Total Station Prism