Extra long standby time in hands-free mode: about 17-20 hours, standby time: about 1400 hours / 60 days. This product has a built-in rechargeable battery that can be randomly charged using the included charger. It is highly recommended to fully charge it before use. Normal full charging time is 3 hours. Dual ConnectionThis mini portable Bluetooth handsfree kit is specially designed to bring you convenience and freedom in wireless communication. It can connect two phones at the same time. DSP noise cancellation Supports high sensitivity microphone with headset and hands-free profiles for HD voice and DSP noise cancellation technology. With an advanced built-in microphone that uses a DSP solution for echo and noise cancellation, this speaker produces excellent full-duplex sound quality for you. Portable DesignPortable design, can be used as a conference call device, including hands-free calling, reading incoming phone numbers, voice control, redialing, mute, rejecting incoming calls. Bluetooth in the car handsfree kit does not require installation and can easily get stuck in the car sun visor.