Features 1. Stainless steel forged ruler body, anti-corrosion, no rust. The edges and corners of the ruler have been carefully polished, which will not hurt hands. 3. High precision laser engraved scales, clear, wear resisting and no fading. 4. Manufactured through multiple workmanship, the ruler is sturdy and durable in use. 5. Rotatable straight ruler design makes the ruler more flexible to use. Specification: Material: Stainless steel  Surface Treatment: Chrome plating Measuring Accuracy: 1mm/1° Optional Size: -#1: Straight Ruler Scale: 100mm, Semicircle Diameter: 90mm -#2: Straight Ruler Scale: 150mm, Semicircle Diameter: 150mm -#3: Straight Ruler Scale: 300mm, Semicircle Diameter: 230mm Package Weight: 75-343g   Package List: 1 * Rotary Protractor Package List