1. Ultra thin design: 18mm thickness, fits snugly on the palm 2. Bluetooth instant messaging: Comes with Bluetooth earphones as standard, "handsfree" operation upon unboxing 4. Navigation menu key mode: Many functions can be set through the menu key, including power, Bluetooth, VOX, incoming call ringtone, Roger beep sound, and button beep function, and can be activated through the+button and - button, which is very convenient, convenient, and efficient. Function: RB39P/RB639P: FRS 22 channel/PMR 16 channel & 9679; Bluetooth & 9679; Voice control & 9679; Call tone Roger Bip & 9679; Button beep sound & 9679; Channel/button lock & 9679; Scanning & 9679; Compression expansion & 9679; Monitoring & 9679; TOT & 9679; Busy Lock & 9679; Low battery alarm & 9679; Power saving & 9679; Restore default settings & 9679; Alarm RB39P General frequency range FRS Rated voltage 3.7V DC Channel 22 Frequency sensitivity 0.5ppm Antenna impedance 50 Working temperature range -20 & 8451;~+55 & 8451; Transmitting RF power 2W/ 0.5W Modulation type FM Modulation distortion