A four-wire overlay touch technology comes in various forms and construction types. It can be activated by a gloved or ungloved finger or any blunt pointing device, and a self-calibrating function reduces and can often eliminate drift. The four-wire resistive design is inherently linear, eliminating the linear compensation patterns required for five-wire products. Applications include handheld and industrial equipment, kiosk, point-of-sale, and other public uses. Products fitting flat panels in sizes from 4.7" to 15" and with an RS-232 controller or chipset controller built in are available.