Balluff's fiber optic sensors are used when a conventional optosensor is too large or too inflexible for the application. Our fiber optic sensors can be combined with either a plastic or fiber optic to form a complete sensor. Their different properties give you maximum flexibility depending on the application. Fiber optic device, light transmitter=LED, connection type=cable, switching output=PNP normally open (NO), PNP normally closed (NC) pins 4-2