WIRELESS SYSTEM: INTERCHANGEABLE WLESS MICROPHONE RCEP R41,H60/OM2 AND B60 ADX10 A BACKPACK OM2 handheld or bodypack system with the ADX10 cardioid backup microphone. This package is designed for rental companies, hotels, presentation events, education and applications where only one transmitter would be required at a time. Please note: it is not possible to use both transmitters simultaneously refer to the AP42 C210 combo pack where both transmitters can be used at the same time.