1、This chalk has longer life span as it is manufactured based on high density manufacturing method which has low wear rate. 2、It is non hand sticky and not stained while using. 3、The drawing line is clear, and does not produce powder. 4、Ergonomic design, very convenient to use. 5、The length of the refill can be adjusted, and the pen-holder can protect the core from damage. Features: This chalk has longer life span as it is manufactured based on high density manufacturing method which has low wear rate. It is non hand sticky and not stained while using. The drawing line is clear, and does not produce powder. Ergonomic design, very convenient to use. The length of the refill can be adjusted, and the pen-holder can protect the core from damage. Specification: Material: Plastic Weight: 68g/ 2.4oz Pen Size: 132*11mm/ 5.2* 0.4inch Package List: 20 x Tailor Chalk Core 2 x Pen Note: Please allow slight error due to manual measurement. Thanks for your understanding.