CAN'T BE - When the earbuds cannot be , please use alcohol to clean the charging contacts. POOR SOUND QUALITY - 1. Choosing the right size eartips. Can provide betterbass, noise isolation and comfortability. 2. Clean the earbuds and mesh. Earwax may block the- sound of the headphones when use for a long time. Powerful Bass and Clear Calls - 13 mm Dynamic driver unit offers deep bass,firm midrange performance and crisp treble for any types of music. Each Earbud Can Use in Single. IPX7 Sport Sweatproof. Compatible Widely. Digital Power Display and Long Battery Life. Colour:Black Material:Plastic Package Contents: 1 * Wireless headphones set Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.