rolling dry erase board. At present, in the developed countries such as Europe, America and Japan, multimedia electronic whiteboard products have been widely used, and a variety of products have been formed according to different application requirements. In developed countries or regions, its application value has been recognized by the society, and the market for products has entered the growth stage and is in the best period of sales. According to statistics from the American Electronic Association ( AEA ), the total sales of global electronic whiteboard products reached US$ 1.7 billion in 2002 , and the main sales regions are the United States, Japan, and the European Union. These three regions accounted for global market share. About 70% . Because the interactive whiteboard products of ultrasonic technology and infrared technology are new products that were introduced only in the second half of 2003 , the products mainly based on resistive film technology and electromagnetic induction technology are mainly on the market, but ultrasonic technology and infrared technology products. It is emerging in the electronic whiteboard market with excellent performance. In 2004 , the sales of American mimio , a manufacturer of ultrasonic wireless positioning interactive electronic products, reached US$ 45.3 million. At present, electronic whiteboard products are mainly used in the field of education and conferences. In Japan, the State Education Commission is. The IQAio GR519 is an upgraded lightweight version based on the original IQAio GR511. The original dual-cavity structure was changed to a bottom-edge structure, so that the minimalist design accommodates modern classrooms and conference rooms. With one IQProjector V2 and one IQView E3821, you can achieve flexible and intelligent classroom.