Features: Engineered with high precise positioning blocks and corrosions resistant alloy construction, this steel rule stop ensures long lasting durability and millimeter perfect accuracy. Features none fade graduations and ergonomic design that provide slip resistant stability while maintaining clear visibility of measurement markings under various lighting conditions. Trusted by engineers, woodworkers, and precise focused DIYers seeking reliabled calibration tools for technical projects requiring exact dimensional control. Optimizes efficiency in metalworking shops, carpentry studios, and laboratory environments where repeatable accuracy is critical for machinery setup or materials cutting operations. The hardened aluminum alloy body resists deformation under pressure, while its compact profile integrates seamlessly with standard measuring rules for enhanced workflow versatility. Specifications: Component: Aluminum alloy 20MM model: size 30x20x8mm, suitable for ruler width 15-20mm, ruler thickness ≤1mm; 26MM model: size 40x20x8mm, suitable for ruler width 24-26mm, ruler thickness ≤1.4mm; 29MM model: size 42x20x8mm, suitable for ruler width 27-29mm, ruler thickness ≤1.4mm; 39MM model: size 52x25x12mm, suitable for ruler width 35-39mm, ruler thickness ≤2.3mm Package Includes: 1pcs Positioning Block note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you donot mind befores you order. 2.Due to the differences between different monitors, the picture may not reflect the actual color. Thanks for your understandings.