customized sound: choose from 22 preset eqs in the soundcore app and customize the tap controls use soundcore's signature bassup preset to boost your bass.long playtime and fast charging: get 9 hours of playtime on a single charge that extends to 28 hours with the charging casecharge soundcore a20i true wireless earbuds for 10 minutes for an extra 2 hours of playtime, so you can charge on the go.designed for portability: soundcore a20i true wireless earbuds are small and lightweight with a compact case. it also comes with a lanyard, so you don't have to worry about space in your bag or pockets.ai-enhanced clear calls: an ai algorithm and 2 built-in microphones ensure that your voice is always heard clearly on calls, no matter how noisy your surroundings are.lightweight and comfortable: enjoy extended listening sessions and exceptional comfort due to the ergonomic and lightweight design of a20i true wireless earbuds.