From the seller:

each unit comes with mic The MXW1 is a hybrid bodypack transmitter compatible with Microflex Wireless systems. It offers both an integrated omnidirectional microphone and an input jack for connecting an ear-worn or lavalier style microphone. The integrated microphone is perfect for picking up speech while the bodypack is on a lanyard or tucked into a shirt pocket, and a belt clip is included for attachment to clothing. All Microflex Wireless transmitters deliver vivid lifelike sound, intelligent wireless performance, encrypted transmission, and advanced rechargeability for conferencing and presentation applications. Compact, low-profile design: Fits comfortably into a shirt pocket or attached to clothing Integrated omnidirectional mic: Clearly captures full-range audio without connecting an external microphone External microphone input: For connecting multiple styles of earworn or lavalier condenser microphones Bi-directional wireless: Enables return channel audio and real-time remote control of all wireless microphone settings Earphone output: Listen to audio from a return channel for translation, cueing, or program material Programmable mute button: Customize local or remote muting behavior per application, with options including push-to-talk, push-to-mute, and external control Standby mode: Enabled remotely during breaks or periods of inactivity to significantly extend battery life when not in use Wide working range: Reliable wireless coverage extends up to 160 feet (50 meters) Out-of-range alert: Emits beeping sound when range is exceeded Wide frequency response: Captures full-range audio for clear voice transmission Easy transmitter linking: Assign the microphone to an access point channel by simply docking it into a networked charging station and pressing “Link” Encrypted wireless: AES 256-bit encryption for secure transmission Advanced Li-ion batteries: Smart lithium-ion internal batteries provide up to 9 hours of continuous use, charge fully in 2 hours, and allow remote monitoring over the network of remaining runtime and charge status in hours and minutes USB charging: Connects to any standard USB power source for “always on” usage. Charge time using SBC-USB adapter: <3.5 hours while mic is in use