Sennheiser SI 1015, IR-control emitter (bottom unit only), 9.5"/1HE, channels: 2.3/2.8 MHz, diverse modes of operation(A+B, A/B, Stereo), Level adjustable, RF-Out (BNC, 50 Ohms), XLR-In, RF-/DC-Out (hardwire), IR-diodes for Monitor, 19"-compatible (GA 1031 CC required), ext. power supply(NT 1015-EU required), optional compatible receiver artnr. 158809