Portable mini wireless speakers for phone mp3 bluetooth receiver hand free car speaker wireless range: up to 10m, impedance: 32 ohms, built-in 2500mah rechargeable battery, compatible with most mobile phones, mp3 players, and computers, features: v3.0+edr. Wirelessly stream music from bluetooth devices bass port for superior sound battery. 2500mah rechargeable battery that provides 4+ hours playback connections. Bluetooth and 3.5mm connections microphone. Built-in microphone to answer calls. Hands-free wirelessly. 10m working distance music playing time: 4-8 hours charging time 1.5 to 2 hours.