Bluedio U (UFO) PPS 8 Drivers High-End Bluetooth headphones Revolution/3D Sound Effect/Aluminum alloy build/Hi-Fi Rank wireless&wired Over-Ear headsets with carrying hard case Gift (Silver and Black) PPS 8 Exclusive Acoustics TechnologyExperience deep and powerful, yet well balanced music with the Bluedio exclusive and innovative 8 driver technology. Each frequency is accurately reproduced for a captivating listening experience. 3D Surround Effect Dramatically enhancing your music doesnt have to be complicated. Simply turn on the 3D surround effect, you'll experience something entirely newa virtual 360 surround sound from the built-in 3D DSP processor, as if in a concert hall. 24-bit High FidelityOptimized for high-fidelity sound, the high-resolution Bluetooth decoder achieves a remarkable new level of speed: up to 24-bit signal processing. It helps reproduce abundant details, let you hear new details and nuances even in your most-played favorites. Top Aviation MaterialAl-Ti Alloy UFO is beautifully crafted with the top-notch aviation material: Al-Ti alloy, which features high strength performance with extreme lightweight (just 337g).Unbreakable, durable and drop resistant. Absolutely secure. Latest Bluetooth 4.1 ChipThe Bluetooth 4.1 is the latest version released from SIG, vastly improved in energy savings. The rechargeable lithium-ion battery charges in just 3 hours with the included USB cable, and delivers up to 25 hours playing time per charge.