Package comes with 1 round center finder compass. Diameter: 200 mm. (The scale does not include the center pin, aluminium/steel combinations). The smallest circle's diameter: 20x2=40 mm; The largest circle's diameter: 80x2=160mm. With laser scale, the round center finder compass is clear to read and not easy to get dirty or damaged. Note: You need to tear off the protective film on the both sides before using. The center marking tool is made of acrylic material, the item is environmentally friendly and durable with good light transmission and high definition. The center finder/compass is perfect for wood turners, arts, crafts, school projects, rough and finish carpenters or use it anywhere you need to draw a circle. Works on wood, poster board, plastic, metal, glass, composites and more.