Legendary sound for small ears.Safe, lightweight and sized for kids, the JBL JR310BT wireless headphones safely deliver up to 30 hours of legendary JBL sound and fun for the youngest music fans. Headphones are designed to never exceed 85dB to protect hearing, with controls that can be easily operated by the children themselves. Kids listen in comfort with custom designed soft padded headband and ear cushions for a soft fit. And every headphone is different as the JBL JR310BT can be customized with the available, reusable stickers for even more fun!Features- JBL Safe Sound- Bluetooth enabled- Built-in mic- 30-hour battery life- Easy controls- Comfort fit- Ultra-portable- Make it yours with JBL Sticker setTechnical Specifications- Driver size: 32mm/1.25" Dynamic driver- Power supply: 5.0V 1.0A-Weight: 115g/0.254 lbs-Battery type: Lithium-ion Polymer (400mAH, 3.7V)- Charging time: <2 hrs from empty- Music playtime with BT on: 30 hrs-Frequency Response: 20Hz – 20kHz-Impedance: 32 ohm-Sensitivity: 90dB SPL @ 1kHz/1mW-Maximum SPL: 80dB- Microphone sensitivity: -40 ± 3dBV @ 1kHz/Pa-Bluetooth version: 5.0-Bluetooth profile version: A2DP V1.3, AVRCP V1.5, HFP V1.6- Bluetooth transmitter frequency range: 2.4GHz – 2.4835GHz- Bluetooth transmitter power: <4dbm- Bluetooth transmitter modulation: GFSK, p/4 DQPSK, 8DPSK-Maximum operation temperature: 45 °C