Amazing tool - templatometer with lock, it is not just an ordinary ruler, but a real helper for any craftsman. You simply press the tool against the object whose shape you want to copy. The plastic pins repeat the contour and you have an exact copy of the shape. The kit comes with a small screwdriver that you can use to adjust how easy or tight the pins move. The metal retainer is not only stronger than the plastic one, but it is also ergonomically shaped. The tool is made of durable ABS plastic. It won't scratch the surface you're working with, won't rust, and isn't afraid of water. The tool has a scale in both inches and centimeters on both sides. Forget about paper templates and complicated measurements. Apply, fix, trace and you're done!