Logitech EasyFit Connector for 2.5mm Plug Requires Logitech EasyFit Headset (sold separately) This kit is compatible with all 2.5mm phone plugs If you have a Logitech EasyFit Headset, then you need a Logitech EasyFit Connector If you upgrade to a new mobile phone model later, you wont need to change your headset Connect the two parts and, plug into your phone and you're set.