Package Dimensions: ‎1.6 x 1 x 0.7 inches; 0.13 Ounces

Working time: 36 hours

Range of Receiving Frequency: 450HZ~4000HZ

Battery Specification: 3V.7; 450mAh (1.67Wh)

Rechargeable Digital Personal Listening Headphones Device with Portable Magnetic Contact Charging Case
Auto Detection To Reduce Screaming：Automatically turn on the device after waring it, and turn off automatically once it is removed, wear it without whistling. 
Super Fast Charge：Charging them 15 minutes then you can get 3-4 hours of playtime. After charging for 2 hours with the charging case, the listening device can work for 12-18 hours, and used the charging box can be extended to 36h.
Comfortable Design: Only 3.6g. The ergonomic listening device can ensure a comfortable fit, boast IPX4 Water & Dust Resistance, and the lightweight design ensures that you will not feel tired however long you listen. 
Tailor-made for Sports：The unique design enhances the firm fit of the headphones and prevent it from falling during vigorous exercise.