[Multifunctional Karaoke System]: -307 Built-in Bluetooth 5.0, working range up to 33 feet. Easy connection to Bluetooth, auxiliary devices, TF/USB input. It can record audio streams via a microphone plugged into a USB/TF card. In addition, the USB port supports mobile power function for charging smartphones/tablets. 【Multiple sound field effects】: Karaoke machine can turn the sound field effects into standard, pop, rock, classical, treble, bass, 307 become karaoke machine to share with your family and friends. 【Powerful Sound Reinforcement System】: Built-in 2*15W speakers, multi-functional design, can reproduce full-range stereo sound. It makes the bass stronger and more balanced, and the "Voice Cancel" function allows you to cancel the singer's voice with one click. Longer battery life]: The built-in rechargeable high-capacity lithium-ion battery for the speaker and high-capacity lithium-ion battery for the microphone allows for up to 3.5 hours of uninterrupted music playback at maximum volume. The speaker acts as a charging station, so it can be easily charged at the same time. With a stable wireless signal of over 80 feet, you can sing as much as you want.