NOVOPHONE Retro Handset with Multifunction Button (Black) [Tempest-2B] Replaceable black cord is 24 inches coiled and extendable to over 6 feet Works with all iPhones and Blackberrys and most Motorola / HTC phones Designed for both 2.5mm and 3.5mm cell phones Multi-function side button allows one to answer/end calls from the handset Does not use any batteries