According to the manufacturer ipf electronic, the ON43 and PN63 retro-reflective sensors can be used in applications where optical systems such as through-beam sensors, retro-reflective sensors or scanners reach their technological limits. The photoelectric sensors do not require a retroreflector as a reference surface - any diffusely reflecting surface is sufficient. The distance to the reference surface is set by teach-in, whereby the PN63 can be taught in via a recess in the housing. Touching this recess with any ferromagnetic tool, such as a screwdriver, is sufficient to start the teach-in process. The ON43 series devices are also equipped with an alignment aid that can be used to position and adjust the touch reflex barriers in combination with an integrated LED. While the ON43 uses a red light LED as the transmitting element, the PN63 uses a red light laser diode in laser protection class 1 as the transmitter. This allows the device to achieve a maximum range of 2000 mm.