The Sony Ericsson HBH-IV840 is a Bluetooth headset that is designed for wirelessly taking calls from a Bluetooth-enabled device. The headset features digital signal processing technology for clear sound transmission and utilizes adaptive frequency hopping technology to reduce wireless interference. It includes technology for automatically pairing with Bluetooth devices as well as automatic volume adjustment which keeps the volume loud in noisy environments. The HBH-IV840 features an enhanced data rate which provides faster transmission, higher bandwidth, and lower power consumption than standard headsets. It is designed with a grey casing and a single multifunction button that is used for answering/ending calls, pairing, and redialing. The headset also runs on a rechargeable battery that provides up to 9 hours of talk time or playback and up to 400 hours standby. The HBH-IV840 has a suggested retail price of $110 and comes with a quick-release neck strap for when the headset is not in use.