Our Patent Products – Auto Eraser’s Features as following 1. No scratch to the chalkboard surface with control box remote system. 2. Easy and fast operation with maximum wiping area in all shapes of chalkboard. 3. A recycling filter box attached to store the chalk powder and equals as a traditional chalk collector vacuum machine. 4. A revolutionary product using the vacuum theory of the vacuum cleaner, with which you can be freed from the chalk powder. Our Standard spec is H: 1.2M and Length is 4.6 -5M And we also welcome any special spec. With just one bottom, wipes out and vacuums automatically the chalk powder produced from the chalkboard and prevents the chalk powder from flying in the air. It not only helps to maintain clean educational environment and save the trouble of wiping the eraser but also time saving and convenience.