Feature:1. This ruler has accurate scale, convenient operation and effective timber saving.2. The centering ruler is specially designed for wood friends, which is convenient for woodworking lovers to quickly find the center and size of the wood circle.3. Acrylic material is environmentally friendly and durable, with good light transmission and high clarity.4. The diameter is 300mm, the thickness is 5mm, and the measurement accuracy is 1.5. Small size, easy to carry and store, convenient to use and with good performance.Specification:Item Type: Center Finder CompassMaterial: Transparent acrylicDiameter: Approx. 300mm / 11.8inThickness: Approx. 5mm / 0.2inMeasuring Range: Approx. 1mm / 0.04inMeasurement Accuracy: 1.Package List:1 x Center Finder Compass