General description The 3X Marine Ruler Parallel Charts is designed for precise graph drawing and mapping. It allows users to draw lines indicating bearings or courses accurately. The ruler operates with two hands, each holding a ruler that moves in parallel to achieve the desired position. Technical specifications Length: 450 mm Material: Plastic Color: Transparent Measurement error: +/- 1-3 cm Usage To use, apply appropriate force to remove the static hand-foot while pushing the moving feet. Alternate the movement of the two feet to maintain parallel alignment and reach the required position. Ensure to avoid static foot displacement during operation. Other information Package Contents: 3 * Graphic parallel ruler Note: Light shooting and different displays may cause the color of the item in the picture to differ slightly from the actual product.