A:AnswerThe CS5129-26 comes with 2 handsets. one that’s sits on the base where the answer machine is and another one that can we plugged in anywhere else in the house. Yes, you can add addition headsets; according to the website up to five additional more.
A:Answeryou would have to consult your phone options & instruction booklet, but I have taken my phone from my upstairs apt, down to my main floor of my apt building, and it worked just fine.
A:AnswerI am not good at sizes, but I believe there is a headset jack, and would recommend you look up the product online to see he sizes and any other helpful information you may need.