It can be cleaned during class time Chalk is not easy to break Material: metal Size: 9 x 1.3 cm Color: Silver Instruction manual: 1. Reduces chalk dust and prevents clothing from getting stained 2. Helps protect fingers from irritation 3. Keeps hands smooth and minimizes chalk residue 4. Helps save chalk and prevents breakage during use 5. Durable for long-term use 6. A practical item for teachers and a thoughtful gift 7. This product fits standard school chalk with a diameter of 9-10mm If your chalk is smaller than 9mm, the clip may be too loose To adjust for larger chalk, widen the clip at the front end If chalk gets stuck inside, remove the small white cap at the top Use a pencil or pen to push it out from the bottom; the process is simple Package includes 3 x Chalk clips Only the above items are included; other items are not included Note: Lighting and display differences may cause slight variations in color between the image and the actual item. Measurement error is +/- 1-3 cm