A:AnswerI am not sure, I bought it to replace my model SL50003 handset which was not holding a charge anymore. The picture looks just like my phone system handsets so it may be an updated model so you may be able to use this model handset.
A:AnswerI bought the extra handset and all I had to do was to set it on the Base Unit for the new 3 handset system for a few moments. It connected fine and works in perfect coordination with the 3 set unit.
Hope that helps.