Hamilton Buhl 15 Watt Waistband Amplifier Go to amazon.com Related posts Expert choice for amplifier 15w FeatureFrequency Response: 100Hz-10kHzInput: TF Card Slot (MicroSD)Input: 3.5mm Microphone JackAC Power: 110-240vUSB and TF card not included Description15 WATT WAISTBAND AMPLIFIER. Waistband amplifier has head-worn mic, TF card slot, & USB port. Rechargeable lithium battery gives 6-8 hours of continuous use indoors or outdoors.