Product Description: bt 4.2V4.2+EDR Charge time- about 2 hours Standby Time -Above 150 hours Talk Time -4 Hours Music Play Time -4 Hours Battery Capacity-250 mAh Frequency response-20Hz-20KHz Support FM-87.5-108.0MHz Support TF Card-128M-32GB Music format-MP3/WMA Features- Volume Control, Built-In Microphone, HD Voice, Rechargeable Active Noise Cancellation- The Over-ear design makes the noise canceling functions come true, it can block the outside noise & lose oneself in the music world. Full control- The headphones are made with all functional buttons. For instance, you can answer and hang-up phone calls; play, pause and skip music tracks and control the volume, as well as to switch from bt to TF card play or FM radio. Note: If the seal is broken then the product can't be returned, unless there is a manufacturing defect.