Feature:1. This equipment can detect batterys voltage.2. Support bluetooth hands-free calls, built-in microphone, secure answer calls.3. Support mobiles A2DP function. Music will be played directly while the mobile phone is connected.4. Mobile phone can be connected automatically when the device powered on.5. Support an external TF card / U disk, can play music files in MP3/ WMA format.6. Integrated car charger of output 5V/3.1A, is available for charging handheld devices in car. Specification:bluetooth Version V3.0+EDRLimit Voltage 9V-36 V Rated Working Voltagae 12V-24 V Sensitivity-42db+/ 3 db 360 Voltage 5V+ / -0.5 Working Current 45m A (max) St&-by Current 25m A (max) Frequency 2.402-2.480 ghzbluetooth Effective Range 10-15 meters Sensitivity-92 d Bm RF Output 4 d Bm FM Frequency 87.5 M Hz-108.0 M Hz Transmitted Power 87d Buv / 107d Buv Microphone Effective Range 2 meters Package Included:1 X Car Charger