... headset -Direct Reading TF card function -Audio output, input -Retractable headband design Multi-function card headsetDirect Reading TF card functionAudio ... speakersRetractable headband design Simple headband design,comfortable to wear,built-in the stainless steel head beams and Wrapped ... expand freely , for a variety of people who wear head shape. Rechargeable systemHeadset built-in charging system,no ...