Bluetrek Metal Evolution Bluetooth Headset - Black [Retail Packaging] Stylish Bluetooth headset with brushed metallic finish on a reinforced aluminum casing Worlds thinnest Bluetooth headsetonly 4mm thick Dual NoiseLock microphone technology cancels background noise for crystal-clear conversations Multipoint technology supports simultaneous active connections with two phones Up to 4.5 hours of talk time; up to 120 hours (5 days) of standby time World's lightest and thinnest noise-canceling Bluetooth headset Razor thin4mm Reinforced aluminum casing Noise-cancellation engine installed to eliminate up to 80 dB environmental background noise effectively Up to 5 hours talk time