Chore-Time Drop Multiflo Tube Switch w/Sensor Plus. The Sensor Plus Drop Tube Switch has a built in safety timer that allows the operator to set a Maximum Run Time for the auger to ensure that it will not continue to operate if the feed bin runs out of feed or if a drop tube is knocked out of a feeder. The Sensor plus also includes a built in heater to dissapate moisture around the sensor. This helps reduce the build up of dust and dirt on the sensor that can lead to false readings.