Always take a closer look at the tech data or the picture of the adaptor when buying something like this - I thought it was just the configuration 2.5mm female to 3.5mm male that I had to pay attention to but, I didn't realiset that it was stereo audio only, but I was trying to use this with my Palm Treo pro phone and didn't notice that there would have to be a 3rd band on the male plug to let the phone controls work with the headset I had in mind. My own fault entirely and absolutely no fault of supplier or item.
Works perfectly with headphones and MP player, so it has not gone to waste.