The band-C Electro-Voice BP-300 Wireless Bodypack Microphone Transmitter is intended for use with the Electro-Voice R300 true-antenna diversity receiver (not included). The bodypack microphone transmitter features 32 user selectable frequency channels and EZsync infrared channel syncing between the receiver and transmitter. Its TA4 connection is compatible with the ULM22 lavalier and HM-3 headworn microphones (sold separately).The BP-300 operates for up to 14 hours on a pair of AA alkaline batteries.