Bluedio U (UFO)Premium Wireless Headphone is first and foremost committed to one thing: the superb sound, achieved by Bluedio exclusive PPS8 acoustics technology and the built-in DSP processor. And its incredible 25 hours battery life is ensured by the latest Bluetooth 4.1 low-power technology. Furthermore, UFO is beautifully crafted with top notch aviation material: Al-Ti alloy, sturdy enough to be durable for long periods of time. Altogether, Bluedio U (UFO) redefines what reference-level wireless audio is all about. About Bluedio Bluedio is a pioneer in portable audio device, providing solutions to professional audio and wireless communication. Bluedio always strives for perfection, fashion and simplicity, focusing on revolutionary innovations. So far, Bluedio has owned over 30 patents, highly praised by consumers over 34 countries. Warranty and Customer Service information 18-month warranty from the date of purchase Email Bluedio Customer Service, get answered under 24 hours To email Bluedio Customer Service: you can click "Your Account" on Amazon, click"Your Orders", find the Bluedio order, click "Contact Seller". In the box Bluedio U (UFO) Bluetooth headphones Audio cable Micro USB charging cable Manual Carry case with a carabiner Specifications Bluetooth version: Bluetooth 4.1 Supported profiles: A2DP, AVRCP, HSP, HFP Drivers: 50mm x 2 ; 20mm x 6 Impedance: 32Ω SPL: 120 dB Frequency response: 5Hz -25000Hz Wireless range: 30ft (no obstructions) Music time: about 25hours Charging time: 3 hours for full charge