Casti Lindy LH500XW Wireless Active Noise Cancelling Headphones Premium, ANC headphones with Bluetooth Technical details Specifications Design: Over Ear Driver: 40mm Neodymium Active Noise Cancellation: 85% reduction of low frequency noise Bluetooth Standard: 4.1 Bluetooth Chipset: CSR8645 Battery Type: Internal Lithium Polymer Battery Life: 30Hr ANC Only, 15Hr Wireless Only, 12Hr ANC & Wireless Impedance: 32Ω passive mode / 100Ω ANC mode Sensitivity: (1mW@1KHz ±3dB): Passive 93dB ANC 103dB Bass 104dB Frequency Response: 20Hz – 20kHz Nominal THD: Passive