4-wire resistive touch screen Prochema has specialized in resistive touch screen for so many years.General size from 2" to 23".Including two types,economical film+glass and unbreakable type. Except for our general size,we can also customize as per your design. 4-Wire resistive touch screen is the preferred solution for low cost applications. It consists of a conductive bottom layer (ITO Glass or Film) and a conductive top layer (ITO Film). The two layers are suspended by many very small spacer dots. When a certain point is touched, the top layer contacts the bottom layer and a voltage charged by the controller is applied to the bottom layer's electrodes. The coordinate X axis of the touch point can be detected by measuring the voltage value thru the top ITO layer and the coordinate Y axis of the touch point can be detected in the same way by changing voltage input to the top layer's electrodes.