... Interactive whiteboard with Built-in Projector Double-User Infrared Interactive whiteboard with Built-in Projector(Built-in Speaker,computer,wireless Board Using 2.4GRF optional)Special ... user write at the same time+projector+mobile stand,all in one set,service at one station;2 Multi-touch, ... letters,the thinnest pen for our whiteboard is 3mm;4 Double use ways for only one board,work as interactive ...