PS-MR1-NSB2-PHOTO SENSOR M18 R 100mm NPN 2M 20.The PS-MR1-NSB2-PHOTO SENSOR M18 R 100mm NPN 2M 20 is your high-precision industrial photo sensor. It's your key to flawless automation, thanks to its sturdy construction, 100mm detecting range, NPN output, and 2-meter connection.