Wireless 2.4 GHz It is couple automatically,easy to operate , up to 4 systems can work together. both transmitter and reciever work on rechargeable lithium battery. work together with battery-powered speakers for a versatile solution, up to 6 hours using time. Easy to Use Wireless Saxophone suitable for many different instruments, such as saxophone, trumpet and many more. SPECIFICATION Frequency range:2.4 GHZ Frequency response:20 Hz - 20 KHz (+- 3 dB) Pairing method:Automatic Power supply:Rechargeable lithium battery Microphone type:Condenser Operational distance:25 metres (82 feet) Operational time:Up to 6 hours Included:6.35 mm (1/4") audio adapter plug and double charger cord الحالة جديد