Package comes with 1 round central finder compass. Diameter: 200mm. (Ladder does not include center pin, aluminum/steel combinations). Diameter of the smallest circle: 20x2=40 mm; Largest circle diameter: 80x2=160mm With the laser scale, the round compass in the center sight is clear to read and not easy to get dirty or damaged. Note : you need to peel off the protective film on both sides before using. The middle marking tool is made of acrylic material, the item is eco-friendly and durable with durable good light transmission and high definition. The centering/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, posterboard, plastic, metal, glass, composites and more.