I purchased three of these from Amazon for my two Sony Ericsson W580i's and one Samsung A737. All three paired quickly and correctly. The only problem was that there was constant buzzing heard by the person receiving the call from all three cell phones. As a test I paired all three of my cell phones with my existing Samsung WEP200 bluetooth headset instead -- no buzzing from any of the phones. I ended up returning all three H500's and purchased the WEP200's instead. I don't know if the three I received were defective, but for sure there were not compatible with my cell phones.