SAW (Surface Acoustic Wave) Touchscreen
Surface Acoustic Wave (SAW) technology uses ultrasonic waves that pass over the touchscreen panel. When the panel is touched, a portion of the wave is absorbed. This change in the ultrasonic waves registers the position of the touch event and sends this information to the controller for processing. Must be touched by a finger, gloved hand, or a soft-tip stylus.
Because the panel is all glass there are no layers that can be worn, giving this technology a high durability factor as well as great clarity. However SAW touchscreen panels are not completely sealable, and contaminants on the surface (eg dirt, dust) can interfere with the functionality of the touchscreen.