1. Newer Version - If you need a Power On/Off button (as demanded by lot customers), please choose our upgrade versions: KM18 Plus/KM22/KM24; also our newer design KM20/KM21 are featured with Sleep/Wake Up function. 2. BROAD COMPATIBILITY - Nulaxy KM18 car fm transmitter works with Bluetooth enabled devices, like iPhone, iPad, iPod, Tablet, Smartphones or MP3, MP4 Players via 3.5mm audio jack. 3. BIG LCD DISPLAY - Car battery voltage level will be detected and displayed on 1.44 inches LCD while the car starts; phone number for incoming calls & name of songs playing through TF Cards could be displayed as well (songs via Bluetooth will not display). 4. CRYSTAL SOUND QUALITY - Nulaxy KM18 utilized most advanced interference and noise cancellation technology, to grant most crystal sound quality. Please be noted, due to radio frequency interference and car ground loop noise, it is almost impossible for any transmitter to produce a perfect audio, but Nulaxy does one of the best work in the market. 5. WHAT IS MORE - Comes with a 5V-2.1A charging port to charge most USB devices; built-in microphone feature supports hands-free talking; support TF/MicroSD Card in FAT format up to 32G; support A2DP; support MP3/WMA format; support AUX output and input.