2.5mm Female to 3.5mm Male 3 Rings Jack Stereo Adapter On/Off enabled Convert 2.5 mm Stereo Cell Phone Headset Adapter allows connection from 2.5mm to any 3.5mm stereo headphone and portable speaker. (BULK PACKAGE) 2.5mm Female to Smartphone 3.5mm Male. End to end is 5 inches long. Stereo-channel enabled if your 2.5mm headset is stereo enabled too.Sleek design made to fit comfortably. Reduce Electromagnetic Radiation (EMR) caused by cell phones and bluetooth headsets. For use with 3.5mm plug on iPhone, Blackberry, Motorola Droid, HTC ,Samsung, LG ,Sony etc. phones. Support one touch button for mute, answer/end or voice activation (Model dependent).