Standard proximity sensor detects metallic objects without contact. Standard type inductive sensors differ in sensing distance (1 mm, 1.5 mm, 2 mm, etc.), sensing side diameter (M4, M5, M8, M12, M18, M30, etc.), head type (Shielded proximity sensor or unshielded proximity sensor) and switching function (pnp no, pnp nc, npn no, npn nc). An inductive proximity sensor is a cylindrical proximity sensor which is used in less challenging applications such as beverage container packaging, automatic drilling machines and shoe rubber press machines.