What's in the box:

Muslady D4-2 Professional 4-Channel UHF Wireless Microphone System Includes 4 Headset Microphones with Bodypack Transmitters + 1 Rack-Mount Receiver for Business Meeting Public Speech Classroom Teaching (Silver)

Features:
This wireless microphone system includes 4 headset microphones + 4 bodypack transmitters + 1 rack mountable receiver, suitable for public speech, classroom teaching, business meeting, etc.
Adopts UHF frequency band to avoid interference; 4 channels and dual antenna design ensure clear and stable signal transmission.
Each microphone has its own volume control knob on the receiver unit for adjusting the volume of the microphone separately to get desired vocal volume.
The receiver has a 6.35mm audio mixing output to connect to speaker, and 4 balance XLR outputs for long distance connection to reduce the noise.
The bodypack transmitters with LED display and receiver with LCD display for showing the working information, which is helpful for you to use and adjust the microphone system.

Specifications:
--Receiver
Color: Black/ Silver(optional)
Oscillation Mode: Quartz Controlled Fixed Frequency
Stability : 10PPM
Sensitivity: 2uV at sinad=12dB
Max. Deviation Range: 50KHz
S/N Ratio: > 103dB
T.H.D.: < 0> Image Rejection: 85dB typical
Spurious Rejection: 75dB typical
Frequency Response: 50Hz-16Khz
Power Supply: DC 12-16V 500mA Power Adapter(included)
Power Adapter: 100-240V US/ EU plug(optional)
Item Size: 48 * 22.5 * 4.5cm / 19 * 8.9 * 1.8in
Item Weight: 2350g / 5.2lbs

--Transmitter
Power: < 30mW> Spurious Emission: < 40dB> Power Supply: 2 * AA Batteries(not included)
Item Size: 11 * 6 * 2cm/ 4.3 * 2.4 * 0.8in
Item Weight: 72g / 2.5oz

Package Size: 53 * 28 * 13.5cm / 20.9 * 11 * 5.3in
Package Weight: 3650g / 8lbs

Note:
You will need an extra speaker or amplifier to connecting with the receiver to make the sound working.
The batteries for transmitters are not included.

Package List:
1 * Receiver
4 * Microphones
4 * Transmitters
2 * Antennas
2 * Mini Wrenches
1 * Audio Cable
1 * Power Adapter
1 * User Manual(English)