Double VHF wireless microphone equipment with 4 selectable frequencies. Allows you to combine up to 4 microphones simultaneously. SMT technology, Oscillating circuits with quartz crystal, Incorporates compression and expansion technology for dynamic range control and higher signal/noise ratio. Squelch system to avoid noise. Battery change indicators. Handheld microphone works with 2 1.5 V (AA) batteries. Belt-pack microphone works with 2 1.5 V (AA) batteries. 5 hours of continuous operation. Includes batteries, 6.35 mm jack audio cable and transport case. Approximate range of 40m in the open air. Frequencies: 174.3 / 188.1 / 189.1 / 194.5 MHz