The OPB840W11Z is a Slotted Optical Switch provide the design engineer with the flexibility of a custom device from a standard product line. Building from a standard housing that utilizes a 9.5mm wide slot. Housings are made from an opaque grade of injection-moulded plastic that minimizes the assembly's sensitivity to visible and near-infrared ambient radiation. Switching of the phototransistor occurs whenever an opaque object passes through the slot and interrupts the beam.