SLXD2 Digital Wireless Bodypack Transmitter Transparent 24-bit digital audio 120 dB dynamic range Digital predictive switching diversity Easy pairing of transmitters and receivers over scan and IR sync Up to 8 hours from 2 AA batteries or optional Shure SB903 rechargeable battery TQG connectivity offers a variety of microphone options Ergonomic, durable plastic construction SLXD4 Digital Wireless Receiver Transparent 24-bit digital audio 120 dB dynamic range