The atw-t902 transmitter features a dynamic unidirectional microphone capsule for excellent gain before feedback and sound quality. It operates using standard AA batteries for extended use of up to 8 hours (with alkaline batteries). Features: easy operation and clear, natural sound quality reliable performance and durable construction specifications: operating frequencies: VHF high band, 169 MHz to 172 MHz modulation Mode: FM maximum deviation: +/-10 kHz dynamic range: >/=90 dB (a-weighted), typical total harmonic distortion: <1% (at 1 kHz, +/-10 kHz deviation) operating range: 200' (60M) typical operating temperature range: 40Deg. To 110Deg.F (4Deg. To 43Deg.C) frequency response: 80 Hz to 13 kHz RF power output: 10 mW- spurious emissions batteries: two 1.5V AA (not included) Battery life: 8 hours (alkaline) dimensions: long: 9.91" (251.71mm) diameter: 2.11" (53.59mm) weight: without batteries: 9.2oz (260.81G)