Koss BT540i Full Size Bluetooth Headphones, Black with Silver Trim Wireless Bluetooth Sound with AptX integrated electronics for enhanced acoustical clarity On-Board Control to change volume, tracks, and answer calls Soft Memory Foam Cushions create the perfect seal and long lasting comfort On Board Microphone Koss PLX40 Dynamic Element precisely tuned to feature crisp highs, robust mids and smooth lows for the ultimate personal listening experience Connectivity technology: Bluetooth, NFC