Mains or Battery Operation. VHF Neckband Microphone System. Bluetooth Receiver. Internal USB Audio Player. FM Radio TunerPower Supply: 230Vac- 50Hz or Internal Re-Chargeable Battery Power Output: 25W Carrier Frequency: 174.1MHz VHF Range: 35m Max Battery Life: 7 Hours (Voice) or 2 Hours (Signal) Frequency Response: 100Hz-12kHz Beltpack Dimensions: 205 x 68 x 25mm Speaker Dimensions: 155 x 183 x 285mm Weight: 76g (Beltpack) & 2.74Kg (Speaker). The H25B is a fully integrated PA unit in an ergonomic ABS handheld housing. Power can be supplied from mains or the internal rechargeable battery to deliver up to 25W output. Hands-free vocal address is made easy and convenient with the supplied VHF wireless neckband system. Built-in Bluetooth receiver and USB media player provide background music playback options- including an FM radio tuner function. Applications include demonstrations- speech reinforcement in educational scenarios and mobile public address.. pa system-portable pa system-audio system