AKG WMS 40 Mini Vocal ISM1, UHF Wireless-System with dynamic handheld transmitter, non Diversity receiver with adjustable balanced jack output, HDAP Technoloiy(High Definition Audio Performance), up to 30 hours with one 1x AA Battery, LED status control on transmitter, Low Battery control on transmitter, On/Off/Mute switch on transmitter, three status LEDs on receiver, frequency ISM 1 863,100 MHz, free to use all over Europe, optional microphone clip 288991