Resistive touch screen can be divided into 4, 5,6, 7 or 8-wired models, which differentiate between the coordinates of touch. As one of the most commonly used, resistive touch screen relies on a touch overlay, constructed by a flexible top layer and rigid bottom layer, divided by insulating spacer dots. The inside surface is coated with a transparent material (ITO) that makes electrical contact when pressure is applied. These voltages are then converted to X and Y coordinates, which are sent to the controller. Whilst resistive screens are durable and easy to integrate, they can only offer 75% clarity.