1、STANDARD TOOL: This surveying prism has a effective diameter of 64mm and a offset of 0mm or ‑30mm, standard and practical. 2、K9 GLASS: K9 optical glass lenses have been carefully polished, and a uniform and delicate coating on the surface can ensure the quality. 3、ANTI WEAR: The prism is designed with ABS protective shell to ensure that the glass prism portion is anti wear, prolongs the service life. 4、WIDE USAGE: This single tilt prism can be used together with a total station for land surveying and has a wide range of uses. 5、MULTI PURPOSE: The total station surveying prism can be used for detection of tunnels, subways, mines, highways, etc. 1 x Surveying Prism1 x Lid1 x Storage Bag Item Type: Surveying PrismMaterial: K9 glass, ABSEffective Diameter: Approx. 64mm/ 2.5inConstant: 0mm/-30mmApplication: Detection of tunnels, subways, mines, highways, etc. Suitable for measuring instruments such as for TrimbleUse: Widely used in various industries such as subways, railway, tunnel, dam, steep slope, etc.