Features: Double Sided Laminated Stain & cracks Comparison Gauges offer precise defect detection with four strong , waterproof surfaces inspection tools for professional component evaluations. Crafted from , warp resistant plastic, these cracks measurement tools feature double sided protective film coating to secure long lasting accuracy in demanding work environments. Ideal for quality process inspectors, construction professional, and industrial maintenance teams requiring stable surfaces imperfection assessment instruments. Perfect for on site concrete inspection, manufacturing quality checks, and infrastructure maintenance projects where portable defect identification tools are essential. The color contrast scale design enables fast visual comparison of surfaces flaws, while the compact 4 gauge set provides versatile measurement solution across multiple industrial applications. Specifications: Component : Plastic Size: about 55x98mm/2.16x3.85inch Package Includes: 4xGap Measuring Ruler note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.