COOLEAD&reg; Bluetooth 4.1 Wireless Sports In-ear Stereo Headphone with Sweatproof Earbuds(Blue) Using latest Bluetooth 4.0 technology compatible V3.0, V2.1, V1,the max transmission distance is up to 30 feet(10m). the ear buds can eliminate the white noise and deliver a clean listening experience, offering you high quality sound enjoyment. This wireless ear buds is tailored for sports lovers and audiophiles.Exercise-proof design makes outdoor sports possible such as running,climbing, driving, skating,camping, fishing and gives you a comfortable exercise experience with music on. Built-in superior lithium battery,it supports up to 5 hours talk/play time and super long standby time up to 120 hours when it is fully charged. This headphones is compatible with IOS and Android smart phones, tablets and any other Bluetooth-enabled devices.It provides you a stunning and fantastic audio trip from your favorite media. With smart 2-link technology,this super bass earphones supports to connect two bluetooth-enabled devices at the same time and realize free switch.