Lentenda Universal Ear Hook Single Earpiece Wireless Bluetooth Stereo Earphone Rechargeable Li-on Battery Wireless Stereo Bluetooth Earphone Music Dreaming Headphone for Mobile Cell Phone Laptop Tablet Standby time: up to 120 hours Charger time: 2-3 hours Operating Voltage: 3.6V Bluetooth Version: Bluetooth V3.0+EDR, compatibility with V2.0 V1.2 Operating Current: &lt;35mA Frequency Range: 2.4026GHz-2.480GHz