... whiteboard, convenience, agility, economy2.ultrasonic,infrared wireless orientation technology, fit to write and painting big area and high density, it has high ... . redisplay each stroke: it can redisplay the content you write according to the real order.5.it sustain the screen kinescope,magnify ... the pen,the width of the line and the background to write random.12. it sustain page down and page up and ...