... annotating, highlight etc (see the specification), and provide free upgrade.Active Buyer:Corporations and government organization with Board rooms ... the model of double screen, vertical and horizontal screen Drive-free, easy maintenance.Sleek, slim & 178 ยบ viewing angle, make the ... , computer, and visualize.. Hand gesture recognizable, rotate, drag, page up/down, zoom in/out, easer. Open platform, user ...