SODIAL(R) 2.5 mm Female to 3.5 mm Male 3 Rings Jack Stereo Adapter On/Off Enabled 2.5mm (3/32 inch) female to Smartphone 3.5mm (1/8 inch) male. End to end is 5 inches long. For use with 3.5mm plug on iPhone 3G/3GS, Blackberry Curve/Storm/Bold, Motorola Droid, Palm Pre, Palm Pixi Phone Headset to iPhone/Blackberry/Smartphone Adapter Reduce Electromagnetic Radiation (EMR) caused by cell phones and bluetooth headsets Stereo-channel enabled if your 2.5mm headset is stereo enabled too