Rolls PM 55P Personal Monitor Amp - monitor input (stereo/mono), XLR microphone in/outputs, Switchable Limiter, phantom power, ground lift, headphone socket (1/4" and mini-jack), separate mic and monitor level, Operates on either one 9 volt battery (alkaline preferred) or the included PS27s power supply.Dimensions 114 x 102 x 35 mm, weight 450 g