Note:the listing have 3 choice,including the whole set,one transmitter,and one receiver.please check out before you pay. For the whole set Feature: Smallest size, lightest earphone monitor. 2.4G wireless technology,low delay, no compression; Support to connect with phone for recoding Support stereo and mono Description: Wireless frequency band: 2.4GHz Delay: 12ms Effective distance: 30 meters outdoor distance or 15 meters wall distance Battery capacity: transmitter 780mAh, receiver 550mAh Dynamic range: >105dB Single body size: 6*4.5*2cm Packing List: 1 x transmitter 1 x receiver 1 x USB cable 2 x audio cable 1 x manual Only one receivers Package include: one receivers with USB cable,audio cable only one transmitter package included: one transmitter with audio and usb cable