Features: 1.Easy To Install: This Plastic L Bar Right Angle Mini Prism Is Small In Size And Light In Weight, Which Makes It Very Convenient To Carry Around With You And Use, And It Is Easy To Install In A Few Minutes. 2.Abs Plastic Housing: This Right Angle Total Station Prism Is Made Of Abs Plastic Housing Which Has Excellent Abrasion Resistance And Durability For Long Term Use And Long Service Life. 3.Excellent K9 Glass Material: This 90 Degree Prism Is Made Of Excellent K9 Glass Material, Which Is Finely Processed With High Accuracy And Can Greatly Improve The Measuring Effect. 4.Clear Reflection: This Portable L Bar Surveying Prism Has A Constant Diameter Of ?25Mm And An Effective Diameter Of 25.4Mm, Which Ensures A Clear And Very Practical Reflected Image. 5.Wide Application: This Right Angle Prism Has A Wide Range Of Applications And Can Be Used For Bridges, Tunnels, Roads, Construction Sites, Subways And So On, Which Is Very Practical. Specification Item Type: Right Angle Prism Material: K9 Glass, Abs Constant: -25Mm Effective Diameter: Approx. 25.4Mm / 1In Application: Inspection Of Tunnels, Subways, Mines, Highways, Etc. Suitable For Measuring Instruments. Use: Widely Used In Industries Such As Subway, Railway, Tunnel, Dam, Steep Slope, Etc.