SLXD2+ Digital Handheld Transmitter with KSM8B Microphone Cartridge (Dualdyne™ cardioid, dynamic, black), Bluetooth remote monitoring and control, high pass filter, FW update via Bluetooth, 24 bit/48 kHz audio conversion, 118 dB dynamic range, external charging contacts, includes 1 carrying bag, 2 AA batteries (optional: SB903 Rechargeable Li-Ion Battery), frequency band G57 (470-608 MHz, tuning range 138 MHz)