Capacitive proximity sensors are capable of detecting both metallic and non-metallic targets such as powders, granulates, liquids and solids. This, along with their ability to sense through non-ferrous materials, makes capacitive proximity sensors an ideal choice for level sensing applications; such as sight glass monitoring and high/low fill level detection of liquid or powder in tanks or hoppers. Many capacitive proximity sensors are tubular in design with common sizes ranging from 12 to 30 mm in diameter with other housing styles available. Housing materials are usually metal and/or plastic (PBT). These are also available in shielded and unshielded mounting versions as well as normally open and normally closed. Capacitive proximity sensors have a limited sensing range, in most cases 3 to 60 mm.