A:Answer Our JBL Tune 130NC TWS comes with a choice of 3 sizes of eartips (S, M, or L). You may choose the right size for your ears so that they will stay in your ears and not fall out during your workout. The charging time is 2 hours (from empty) and the battery life is 40 hours, delivering JBL's Pure Bass Sound. It has a frequency response that can go down to 20 Hz and a dynamic drive size of 5.8mm, allowing you to experience its Pure Bass Sound feature for every music track.