GW100 Wireless Series Since 1953 Grado Labs has adapted at our own pace, and the first wireless Grado headphone is only the first step in what’s to come. We took our time to get the sound just right and made no compromises in the GW100. Nothing is lost except the wires. Inside the GW100 are none other than our signature Grado drivers. These speakers are the same ones we build for our wired headphones, which are finely tuned for the different enclosures we use. Grado Labs' first wireless headphone is no different, with drivers configured specifically for them. The desired sonic capabilities of the GW100 would not be possible without decades of experience in driver design. Audio Specs: Bluetooth Version: 4.2 with apt-XBattery Capacity: 320mAHWorking Distance: 10mBattery Life: 15 hours**Frequency Response: 20Hz~20KHzMic Sensitivity: 42dB +/- 3dBTransducer Type: DynamicOperating Principle: Open AirSPL 1mW: 99.8 dBNominal Impedance: 32 ohmsDriver Matched dB: .05 dB*As compared to our wired headphones. Leakage reduction varies in certain situations. This is based on a reasonable distance, angle, and genre of music played.**Based on 50% volume throughout playtime. Battery varies due to volume and musical genre. Included Accessories: Headphones, Warranty, Grado story-sheet, micro-USB charging cable, 3.5mm audio cable