? Built-in Bluetooth RF wireless module, meets the latest Bluetooth 2.1+ED standardSupports Bluetooth stereo sound, perfect sound quality and outstanding bass effectSupports iPhone, iPad and all telephones which have Bluetooth functionPlaying music ups to 8 hours, audio transmission distance is 10MWith Bluetooth music controlling function, can control play/pause, previous/next song functionPower supple mode: built-in Lithium battery, USB cable power supplyWith Bluetooth hands free function, built-in high fidelity chip, can answer callsWith 3.5 stereo audio jack, can connect into many device: laptop/computer, telephone and MP3/MP4With aluminum alloy material designTechnology parameter:Rated power: 4Ω, 3WSpeaker: 1.75 inchesSensitivity: 80dB ± 2dBSNR: ≥80dBDistortion: ≤0.3%