Stable signal transmission - The transmission distance reaches 164ft (50 meters). 20 UHF channels are optional, free from signal interference, frequency band 902-928MHz. High-capacity built-in rechargeable lithium battery--One is divided into two charging cables to charge 2 transmitters at the same time, which greatly reduces the charging time. It only takes 2 hours to fully charge the device and can work for 6 hours. Lightweight, Plug and Play -- The transmitter is lightweight at only 2.4 ounces. Mushroom-shaped heads rigid plastic stems interlock,Simple installation, automatic signal synchronization connection, plug and play. ?Non - mark adhesive--tear off without damage to the instrument paint. ?2 Transmitters with 1 Receiver - The two receivers simultaneously receive the sound from the cello, making the sound quality clearer and more perfect. ?Microphones specially designed for cellos - Pick up the sound of the cello precisely and eliminate other noises.