The SR40 mini2 receiver provides three status LEDs each for channels 1 and 2, indicating ON/OFF status, received signal strength (RF OK), and audio clipping (AF CLIP). The VOLUME control sets the level at the ¼" output jack. The illuminated ON/OFF button switches both channels on and off simultaneously. The PT40 mini bodypack is probably the smallest and lightest transmitter in its class. A reliable mini XLR input allows you to connect every compatible AKG miniature microphone. The rugged HT40 mini handheld transmitter features an ON/OFF/MUTE switch and a sturdy wire-mesh cap protecting the cardioid dynamic microphone element. Battery life is the same legendary 30 hours off single AA battery as for the standard WMS40 models, reducing the need to replace batteries.