Never-Drop Design-Ergonomicandnever-dropdesign.Uitraliht-weightwithsliconeearbudsguarantees comfortablewearingforalongtime. The charging box has afast charginghigh quality built-inbattery of4000 mAh.When fully charged, the charging box can support360 hoursof earbuds. After each listening, just put the earbuds back into the chassis to charge. Superior technology means superior sound:Experience top-shelf sound quality and bask in its incredibly powerful bass, crisp mid-highs, and crystal clear vocals, and have your own personal bubble that encompasses you in premium acoustics.