Applied Microphone Technology AMT HR 3 Harmonica-Microphone, The microphone is intended to fit different sized harmonicas from diatonic to 16 hole and adjusts by a thumb and an allen screw to fit different sized instruments. The inline preamp ( 48v required) can be placed on the floor, a belt clip for mobility, or in your pocket. A low roll-off filter as well as a dB cut are including on the inline preamp.Includes soft carry case, ERTS clamp and pre amp,,