Features: Scale for transparent surfaces can view the entire page. Pure copper-gasket after polishing, not easy to oxidation, wear and durable. Made of high quality plastic ensure durability even under extreme conditions. Good transparent and strong and durable, exquisite appearance, imported ink printing scale. The manual ruler provides accurate measurements through the aluminum chain, providing appropriate tension for drawing straight line parallel to another line or reference points. Specifications: Material: PVC Length: Approx. 45cm/17.72in Package Includes: 1x Parallel Ruler note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.