The BOYA BY-WM3D 2.4GHz wireless microphone system features one transmitter and one receiver, both of them are compact and lightweight. Ultra-compact Wireless Microphone System Small size & light weight, the transmitter is only 10.5g (0.37oz). And the BY-WM3D is equipped with a charging case that can charge and pair the transmitter and receiver. After one full charge, the TX/RX can continue working for about 4.5/8 hours.