The original replacement headset for CS10 and CA10 has been discontinued. This item is an alternative. It is the Plantronics M175C convertible headset (comes with both headband and earhook, click on both photos to enlarge view) with noise canceling microphone and inline volume/mute control on cord. The cord comes down to the 2.5mm plug that goes into the remote control belt pack of your Plantronics CA10, CS10, CT10, CA10CD, CT12, CT11, CT14 and Avaya LKA10 or Avaya 10U100. Everything is included with this item (the headset, wearing attachments and the connector cable). The headset is covered by 1 year factory warranty.