SOLID HARDENED STEEL CONSTRUCTION: This heavy duty ruler self defense tool is crafted from 5 mm thick high‑strength carbon manganese steel, precision quenched and reprocessed for exceptional toughness and stability. Its rugged build far outlasts ordinary metal rulers, resisting bending, warping, and daily wear in demanding environments. DOUBLE SCALE FOR MEASUREMENT: Featuring dual‑sided markings in inches and millimeters, this 20 inch and 50 cm metal straight edge offers clear, wear‑resistant graduations for long‑term accuracy. Ideal for construction layouts, workshop measurements, office drafting, and DIY projects where , repeatable measurements matter. MULTIFUNCTIONAL SAFETY ESSENTIAL: Beyond a precision measuring tool, this heavy duty ruler can serve as an emergency striking device, such as for breaking vehicle windows in critical situations. A practical addition to car safety kits or home emergency gear, it conveniently combines everyday measurement with reliable emergency preparedness. PORTABLE AND EASY TO STORE: The 0.2 inch thick manganese steel ruler comes with a protective case for safe storage and transport. Slim yet solid, it fits easily in a car glove box, tool bag, desk drawer, or backpack. Whether on job sites, during long road trips, or at home, you can quickly access it whenever it is needed. WIDE APPLICATION & RELIABLE PERFORMANCE: Designed for durability and versatility, this heavy duty metal ruler suits professionals and DIYers alike. Use it as a straight edge for cutting, marking, and layout, or keep it on hand as part of your emergency response kit. Its compact, robust design ensures dependable performance in varied scenarios. Color: As Shown Material: Metal Package Contents: 1*ruler 1*protective cover Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1