The MPP-11 and MPP-21 systems standardly operate on external shop air. Some customers do not have an external air source and therefore then require the optional vacuum pump for running the pick & place function on our MPP-11 and MPP-21. Please note that the MPP-11 and MPP-21 systems have both a pick & place and dispensing function. The A-0190 vacuum pump only works for the pick & place function. The dispenser function always requires external shop air.