An accurate square used to check if a corner is 90 degrees. It can also be used as a guide for marking. MATSUI Precision Try Squares Precision try squares from MATSUI are highly accurate instruments made of rustproof stainless steel. Theseprecision squares are welded firmly together with electricity to prevent it from loosening or wobbling over time. The edges are polished to a smooth surface with an accurate polishing machine to increase accuracy.In addition to the inside and outside scales, the thin blade features a Ura-me edge. This scale lets you determine the largest possible square cross-section that can be obtained from a round piece of timber. Simply place the square’s Ura-me scale across the face of the round timber to read off the value. One graduation mark along the Ura-me edge equals 1.414 mm (square root of 2). Matsui are renowned for making precision measuring instruments. This square is used for marking 90 degrees angles and can be used for measuring and marking out joints.