Feature: This equipment can detect batterys voltage. Support bluetooth hands-free phone calling via its build-in microphone. Support mobilea A2DP function, Music will be played directly while the mobile phone is connected. Mobile phone can be connected automatically when the device powered on. Support an eaternal TF card/U disk, can play music files in MP3/WMA format. Integrated car charger of output 5V-2100m A, is available for charging handle devices in car. Specification:bluetooth Version: V3.0+EDRFrequency: 20 Hz~20 K Hz Sensitivity: -42db+/3db 360 Voltage: 5V+/-0.5 Working Current: 45m A (max) St&-by Current: 25m A (max) Frequency: 2.402~2.480ghz Effective Range: 5 M Sensitivity: -92d Bm RF Output: 4d Bm Frequencies:FM: 87.5 M Hz-108.0 M Hz Transmitted Power: 87d Bv/107d Bv Effective Range: 2m Package Included:1 X FM Transmitter 1 X English User