Features: 1.[High Precise Land Surveying] This Mini Prism Is Designed For Use With Total Stations, Utilizing A 17.5Mm Constant To Reduce Errors And Ensure Millimeter Level Accuracy In Land Measurement. 2.[Precisely Ground Glass Components] The Mini Prism Features: Precisely Ground Glass Components That Are Meticulously Crafted To Ensure Overall Measurement Accuracy, Delivering Reliable And Consistent Results In Surveying Applications. 3.[Heavy Duty Housing] The Housing Of The Mini Prism Is Constructed From Heavy Duty Polymer, Capable Of Withstanding Various Weather Conditions And Daily Wear And Tear, Ensuring Long Lasting Performance In The Field. 4.[Versatile Applications] This Mini Prism Is Suitable For A Wide Range Of Applications, Including Tunneling, Subways Construction, Mining, Highway Inspection, And More, Making It A Versatile Tool For Various Surveying And Engineering Projects. 5.[4 Prism Poles] The Mini Prism Comes With Four Measuring Poles, Allowing For Easy Assembly And Disassembly, Providing Convenience And Flexibility. Specification Item Type: Total Station Surveying Prism? Material: K9 Optical Glass, Abs Effective Diameter: Approx. 25.4Mm/1In Constant: +17.5Mm Application: Ideal For Railways, Tunnels, Mines, And Highways, Suitable For Measurement Instruments. Use: Widely Used In Industries Such As Subways, Railways, Tunnels, Dams, And Steep Slopes.