1.Size Convex Numbers: 16, Precision: ±0.1mm, Measurement Range: 25 50mm, Height: 70mm / 2.76inch, Thickness: 10mm / 0.39inch, Length: 74mm / 2.91inch, Width: 23mm / 0.91inch 2.Material The radius gauge is made of alloy steel, heat processed hardened finish, high strength, good resilience, elegant appearance, anti rust, and corrosion. 3.Feature The radius measuring instrument has two types of leaves, each leaf is clearly marked, convenient to identify which leaf you need. So it can check the convex and concave surfaces. The convex pattern is used to detect the concave surface arc, and the concave template is used to detect the convex surface arc. 4.Application They measure accurately and have almost no errors, which will help you quickly and easily check the radius of tools. Different shapes and sizes will meet your various needs. Very useful gauge for tool die makers, machinists, and many other workers to check the radius of tools.