Total Station Surveying Prism 25.4mm Effective Diameter 17.5mm Constant Survey Mini Prism with 4 Poles for Topcon1[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.