Bluetooth specification: 2.0. DSP technology, full duplex, noise and echo suppression. USB port for software update and charge. Characteristic design, super-light and ultra-thin. Independent FM wireless earpiece to protect your privacy. Built-in high intelligent microphone and powerful speaker. Full frequency (88MHz-108MHz) optical and 6 frequencies modulation to transfer the voice to the car stereo. Caller ID and English name display. Incoming call number store, can store 200 groups number then call back. Rechargeable lithium battery. Answer/end/reject a call, voice dialing, last call redialing and call switching between phone and car kit function. Support two mobile phone connections. Voice record and playback, volume control. Bluetooth profile supported: headset and hands-free profile. Frequency range: 2.4GHz spectrum. Load input voltage: DC12V-24V. Operating temperature: 0 ° C ~ 50 ° C. Storing temperature : -10 ° C ~ 60 ° C.