Features: Comes with different diameter holes, this square can matching a variety of mainstream screw size. Find the right hole in a second, then fix the screw for drilling work. Adopts aluminum treatments, strong structure, not easy to deformation, can maintain accuracy. Easy to hold with one hand for long time. Ruler have a widened base, when you fix screws, cut, or draw lines, fit the base to edges of the wood, ruler is not easily slide. Provide double stability to ensures accuracy of work. All scales are in units. Accurate and clear spacing, easy to read, long time without wear. Available for drawing 45/90° Angles, balance, vertical line and drilling positioning, can also be used for positioning platform height Specifications: Component:Aluminum Size:4.5inch/7inch/12inch Package Includes: 1Pc Triangles Ruler note: 1.Please allow 1-2cm errors due to manual measurement, making sure that you not mind before order. 2.Due to the differences between different monitors, the picture may not reflect the actual of the item.