The DS30 line is a proximity style sensor with a single PNP or NPN output capable of detecting virtually any target within its 2-meter range. Unlike many sensors that will see a brighter target as closer to the sensor than a darker target, the DS30 is said to detect flat black and shiny targets at the same range repeatedly. Some high performance sensors have color-independent detection and measurement as well, but this type of performance has never been offered in a sensor the size and at the price of a DS30, says the vendor. SICK Inc.www.sickusa.com800.325.7425